Ivms-USMLE Step 1 Review Course- Summative Assessment-pharmacology

1. Which of the following is an antineoplastic agent that has been shown to help patients with rheumatoid arthritis?

Valdecoxib

Ketorolac

Methotrexate

Entocort

Auranofin

The answer is C. From the presented list, only methotrexate is known to be an antineoplastic agent. This medication has been used successfully in rheumatoid arthritis and other rheumatologic conditions. Valdecoxib (A) is a COX-2 inhibitor that has been recently removed from the market. Ketorolac (B) is a powerful analgesic used for multiple autoimmune conditions. Entocort (D) is a glucocorticoid that can be used in some arthritides. Auranofin (E) is a gold compound that is rarely used anymore.

Explanation

The answer is C. From the presented list, only methotrexate is known to be an antineoplastic agent. This medication has been used successfully in rheumatoid arthritis and other rheumatologic conditions. Valdecoxib (A) is a COX-2 inhibitor that has been recently removed from the market. Ketorolac (B) is a powerful analgesic used for multiple autoimmune conditions. Entocort (D) is a glucocorticoid that can be used in some arthritides. Auranofin (E) is a gold compound that is rarely used anymore.

2. Which of the following is an antidote for iron overdose?

Protamine

Deferoxamine

Vitamin K

Fresh frozen plasma

Charcoal

The answer is B. Deferoxamine is an iron-chelating agent and as such can be given in cases of iron supplement overdose. Protamine (A) is an antidote for heparin. Vitamin K (C) and fresh frozen plasma (D) are given for coumarin reversal. Charcoal is an agent sometimes used for gastric lavage.

Explanation

The answer is B. Deferoxamine is an iron-chelating agent and as such can be given in cases of iron supplement overdose. Protamine (A) is an antidote for heparin. Vitamin K (C) and fresh frozen plasma (D) are given for coumarin reversal. Charcoal is an agent sometimes used for gastric lavage.

3. . Which of the following would be useful in treating nocturnal enuresis?

. Mannitol

Indomethacin

Furosemide

Vasopressin

Probenecid

The answer is D. Vasopressin use can be tried in cases of recalcitrant nocturnal enuresis. Mannitol is most commonly used in management of cerebral edema (choice A). Indomethacin can occasionally be used as an antidiuretic agent in diabetic patients (choice B). Furosemide is used in congestive heart failure (choice C). Probenecid is used in treatment of gout (choice E).

Explanation

The answer is D. Vasopressin use can be tried in cases of recalcitrant nocturnal enuresis. Mannitol is most commonly used in management of cerebral edema (choice A). Indomethacin can occasionally be used as an antidiuretic agent in diabetic patients (choice B). Furosemide is used in congestive heart failure (choice C). Probenecid is used in treatment of gout (choice E).

4. Which of the following can be used to treat a 22-year-old with a recent diagnosis of schizophrenia?

Baclofen

Haloperidol

. Chloral hydrate

Phenobarbital

Imipramine

The answer is B. Haloperidol is an antipsychotic used in acute psychotic attacks and for the treatment of schizophrenia. It functions predominately as a dopamine-receptor blocker, predominately at the D2 receptor. Baclofen is a GABAB receptor antagonist that is used in the treatment of spinal cord injuries. Choral hydrate is a hypnotic agent that works similarly to ethanol. Phenobarbital is a barbiturate used in the treatment of seizures and as an anesthetic. Imipramine is a tricyclic antidepressant and is not used in schizophrenia.

Explanation

The answer is B. Haloperidol is an antipsychotic used in acute psychotic attacks and for the treatment of schizophrenia. It functions predominately as a dopamine-receptor blocker, predominately at the D2 receptor. Baclofen is a GABAB receptor antagonist that is used in the treatment of spinal cord injuries. Choral hydrate is a hypnotic agent that works similarly to ethanol. Phenobarbital is a barbiturate used in the treatment of seizures and as an anesthetic. Imipramine is a tricyclic antidepressant and is not used in schizophrenia.

5. A 32-year-old woman being treated for an acute exacerbation of lupus erythematosus complains of pain on eating. What is the most likely causative agent?

Oxytocin

Androlone

Vasopressin

Prednisone

Clomiphene

The answer is D. Prednisone, a steroid commonly used to treat exacerbations of lupus erythematosus, can cause peptic ulcer disease due to the inhibition of the prostaglandins that normally protect the mucosa.

Explanation

The answer is D. Prednisone, a steroid commonly used to treat exacerbations of lupus erythematosus, can cause peptic ulcer disease due to the inhibition of the prostaglandins that normally protect the mucosa.

6. Which of the following should be considered to treat an acetominophen (APAP) overdose in a 17-year-old female?

Trientine

Sorbitol

N-acetylcysteine

Ipecac

Diazepam

The answer is C. N-acetylcysteine is used in the case of APAP toxicity. It provides sulfhydryl groups for the regeneration of glutathione stores in the body. Trientine is a copper-chelating agent sometimes used in Wilson's disease. Sorbitol is used as a cathartic to help remove toxins from the gastrointestinal tract. Ipecac has been used to induce emesis in cases of toxic ingestions. Diazepam can be used to prevent seizures when strychnine is ingested.

Explanation

The answer is C. N-acetylcysteine is used in the case of APAP toxicity. It provides sulfhydryl groups for the regeneration of glutathione stores in the body. Trientine is a copper-chelating agent sometimes used in Wilson's disease. Sorbitol is used as a cathartic to help remove toxins from the gastrointestinal tract. Ipecac has been used to induce emesis in cases of toxic ingestions. Diazepam can be used to prevent seizures when strychnine is ingested.

7. Which of the following inhibit HMG-CoA reductase?

Nicotinic acid

Rosuvastatin

Ezetimibe

Cholestyramine

Gemfibrozil

The answer is B. Rosuvastatin is an HMG—CoA reductase inhibitor. Nicotinic acid (A) inhibits the process of esterification of fatty acids, thereby reducing plasma triglyceride levels. Ezetimibe (C) reduces cholesterol absorption. Cholestyramine can bind bile acids and prevents their enterohepatic circulation (D). Gemfibrozil (E) reduces hepatic synthesis of cholesterol.

Explanation

The answer is B. Rosuvastatin is an HMG—CoA reductase inhibitor. Nicotinic acid (A) inhibits the process of esterification of fatty acids, thereby reducing plasma triglyceride levels. Ezetimibe (C) reduces cholesterol absorption. Cholestyramine can bind bile acids and prevents their enterohepatic circulation (D). Gemfibrozil (E) reduces hepatic synthesis of cholesterol.

8. A Which of the following is a potential side effect of clozapine?

Cholestatic jaundice

QT prolongation

Agranulocytosis

Photosensitivity

Galactorrhea

The answer is C. Agranulocytosis occurs more frequently with clozapine than with other agents, requiring routine blood tests. It is the only agent that improves the negative symptoms of schizophrenia. Cholestatic jaundice and photosensitivity are common with chlorpromazine. Galactorrhea is a side effect of older high-potency agents that block dopamine. QT prolongation is a complication of agents such as thioridazine and ziprasidone.

Explanation

The answer is C. Agranulocytosis occurs more frequently with clozapine than with other agents, requiring routine blood tests. It is the only agent that improves the negative symptoms of schizophrenia. Cholestatic jaundice and photosensitivity are common with chlorpromazine. Galactorrhea is a side effect of older high-potency agents that block dopamine. QT prolongation is a complication of agents such as thioridazine and ziprasidone.

9. Clonidine works by

Activating β1-adrenergic receptors

Activating α1-adrenergic receptors

Activating β2-adrenergic receptors

Activating α2-adrenergic receptors

Blocking β-adrenergic receptors

The answer is D. Clonidine activates prejunctional α2-adrenergic receptors in the CNS to reduce sympathetic tone, thereby decreasing blood pressure. Activation of α1-adrenergic receptors increases blood pressure, and such agonists are used in the treatment of hypotension. β 1-adrenergic agonists are used primarily for increasing heart rate and contractility. β2-adrenergic agonists are used to dilate airways in the management of asthma. β-blockers are used in the treatment of angina and hypertension.

Explanation

The answer is D. Clonidine activates prejunctional α2-adrenergic receptors in the CNS to reduce sympathetic tone, thereby decreasing blood pressure. Activation of α1-adrenergic receptors increases blood pressure, and such agonists are used in the treatment of hypotension. β 1-adrenergic agonists are used primarily for increasing heart rate and contractility. β2-adrenergic agonists are used to dilate airways in the management of asthma. β-blockers are used in the treatment of angina and hypertension.

10. Which of the following drugs inhibits xanthine oxidase?

Colchicine

Indomethacin

Probenecid

Clofibrate

Allopurinol

The answer is E. Allopurinol is a xanthine oxidase inhibitor and is most commonly used in treatment of gout. It is not used for acute attacks, but rather for prevention of recurrent episodes. Colchicine (choice A) may be used for an acute episode, as well as in long-term therapy; however, it has a high incidence of side effects. Indomethacin (choice B) is useful for symptomatic treatment of gout. Probenecid (choice C) is also useful for prophylaxis of gout; however, it is not a xanthine oxidase inhibitor. This agent inhibits secretion of organic acids. Clofibrate (choice D) is used in treatment of hypercholesterolemia.

Explanation

The answer is E. Allopurinol is a xanthine oxidase inhibitor and is most commonly used in treatment of gout. It is not used for acute attacks, but rather for prevention of recurrent episodes. Colchicine (choice A) may be used for an acute episode, as well as in long-term therapy; however, it has a high incidence of side effects. Indomethacin (choice B) is useful for symptomatic treatment of gout. Probenecid (choice C) is also useful for prophylaxis of gout; however, it is not a xanthine oxidase inhibitor. This agent inhibits secretion of organic acids. Clofibrate (choice D) is used in treatment of hypercholesterolemia.

11. Which of the following is a common adverse effect of quinidine?

Cinchonism

Lupuslike syndrome

Seizures

Constipation

Pulmonary fibrosis

The answer is A. Cinchonism, or ringing in the ears and dizziness, is common after quinidine use. Lupuslike syndrome (B) can be observed after the use of procainamide. Seizures may occur with lidocaine use (C). Diarrhea can occur with the use of quinidine, not constipation (D). Pulmonary fibrosis is a long-term complication of amiodarone use (E).

Explanation

The answer is A. Cinchonism, or ringing in the ears and dizziness, is common after quinidine use. Lupuslike syndrome (B) can be observed after the use of procainamide. Seizures may occur with lidocaine use (C). Diarrhea can occur with the use of quinidine, not constipation (D). Pulmonary fibrosis is a long-term complication of amiodarone use (E).

12. Which of the following is a complication of phenytoin use?

Hepatotoxicity

Gingival hyperplasia

Thrombocytopenia

Aplastic anemia

Stevens-Johnson syndrome

The answer is B. Gingival hyperplasia is a unique side effect of phenytoin, which can be partially avoided by meticulous oral hygiene. Several anticonvulsants can cause hepatotoxicity, including valproic acid and felbamate. Aplastic anemia is a rare, but potential complication of carbamazepine, ethosuximide, and felbamate. Valproic acid is also associated with thrombocytopenia. Ethosuximide has been associated with a severe form of erythema multiforme, the Steven-Johnson syndrome.

Explanation

The answer is B. Gingival hyperplasia is a unique side effect of phenytoin, which can be partially avoided by meticulous oral hygiene. Several anticonvulsants can cause hepatotoxicity, including valproic acid and felbamate. Aplastic anemia is a rare, but potential complication of carbamazepine, ethosuximide, and felbamate. Valproic acid is also associated with thrombocytopenia. Ethosuximide has been associated with a severe form of erythema multiforme, the Steven-Johnson syndrome.

13. An 81-year-old man with a history of coronary artery disease and a recent diagnosis
of hypothyroidism presents to the emergency department with an acute myocardial infarction (MI). What is the most likely causative agent?

Medroxyprogesterone

Levothyroxine

Thiocyanate

Flutamide

Diethylstilbestrol (DES)

The answer is B. Elderly patients with subclinical hypothyroidism are at risk for arrhythmias, angina, or myocardial infarction (MI) if they have underlying cardiovascular disease when they begin treatment with thyroid hormones such as levothyroxine. These potential adverse effects occur because of increased cardiovascular work load as well as the direct effect of thyroid hormone on the heart.

Explanation

The answer is B. Elderly patients with subclinical hypothyroidism are at risk for arrhythmias, angina, or myocardial infarction (MI) if they have underlying cardiovascular disease when they begin treatment with thyroid hormones such as levothyroxine. These potential adverse effects occur because of increased cardiovascular work load as well as the direct effect of thyroid hormone on the heart.

14. What is the mechanism of action of β-blockers in heart disease?

Prolongation of AV conduction

Activation of the sympathetic system

Promotion of automaticity

Increase in heart rate

Arteriolar vasodilation

The answer is A. Beta-blockers prolong AV conduction. The reduce sympathetic stimulation (B). These agents depress automaticity (C). Beta-blockers decrease heart rate (D), and can cause arteriolar vasoconstriction (E).

Explanation

The answer is A. Beta-blockers prolong AV conduction. The reduce sympathetic stimulation (B). These agents depress automaticity (C). Beta-blockers decrease heart rate (D), and can cause arteriolar vasoconstriction (E).

15. A neurosurgeon decides to start a patient on a diuretic that works by altering the diffusion of water relative to sodium (an osmotic diuretic) that is helpful in reducing cerebral edema. Which agent did the physician likely prescribe?

Furosemide

Hydrochlorothiazide

Spironolactone

. Acetazolamide

Mannitol

The answer is E. Mannitol is an osmotic diuretic frequently used in management of cerebral edema caused by various insults. This agent works by altering the diffusion of water relative to sodium by “binding” the water, with a resultant reduction of sodium reabsorption. Furosemide and hydrochlorothiazide act by directly altering reabsorption of sodium in various parts of the nephron (choices A and B). Spironolactone (choice C) antagonizes mineralocorticoid receptor. Acetazolamide inhibits carbonic anhydrase (choice D).

Explanation

The answer is E. Mannitol is an osmotic diuretic frequently used in management of cerebral edema caused by various insults. This agent works by altering the diffusion of water relative to sodium by “binding” the water, with a resultant reduction of sodium reabsorption. Furosemide and hydrochlorothiazide act by directly altering reabsorption of sodium in various parts of the nephron (choices A and B). Spironolactone (choice C) antagonizes mineralocorticoid receptor. Acetazolamide inhibits carbonic anhydrase (choice D).

16. AOrganophosphate poisoning is treated with

Pralidoxime (2-PAM)

Parathion

Amyl nitrate

Bethanechol

Nicotine

The answer is A. Pralidoxime reactivates acetylcholinesterase to reverse the effects of exposure to organophosphates, of which parathion is actually an example. Amyl nitrate can be used in cases of ingestion of the cytochrome oxidase inhibitor cyanide. Bethanechol is a direct-acting cholinergic agonist used to treat urinary retention and overdose and can result in symptoms similar to organophosphate poisoning. Nicotine is sometimes found in insecticides and can cause vomiting, weakness, seizures, and respiratory arrest.

Explanation

The answer is A. Pralidoxime reactivates acetylcholinesterase to reverse the effects of exposure to organophosphates, of which parathion is actually an example. Amyl nitrate can be used in cases of ingestion of the cytochrome oxidase inhibitor cyanide. Bethanechol is a direct-acting cholinergic agonist used to treat urinary retention and overdose and can result in symptoms similar to organophosphate poisoning. Nicotine is sometimes found in insecticides and can cause vomiting, weakness, seizures, and respiratory arrest.

17. A 63-year-old male, with a history of multiple myocardial infarctions is admitted for shortness of breath. A diagnosis of congestive heart failure is made on clinical grounds, and a cardiologist orders a positive inotropic agent for his heart failure. He is also concerned about maintaining perfusion to the kidneys, so an agent that increases renal blood flow is also desirable. Which of the following agents produces both of these desired effects?

Epinephrine

Dopamine

Isoproterenol

Terbutaline

The answer is B. Dopamine is useful in the management of congestive heart failure, as it has both positive inotropic effects on the heart and preserves blood flow to the kidneys. Epinephrine and isoproterenol increase cardiac contractility while decreasing peripheral resistance. Albuterol is a β1 agonist used in the management of asthma, and terbutaline is another β agonist used to suppress labor, in the event of threatened labor of a premature fetus.

Explanation

The answer is B. Dopamine is useful in the management of congestive heart failure, as it has both positive inotropic effects on the heart and preserves blood flow to the kidneys. Epinephrine and isoproterenol increase cardiac contractility while decreasing peripheral resistance. Albuterol is a β1 agonist used in the management of asthma, and terbutaline is another β agonist used to suppress labor, in the event of threatened labor of a premature fetus.

18. Which of the following is an alkylating agent that may cause hemorrhagic cystitis and cardiomyopathy?

Azathioprine

Cyclosporine

Tacrolimus

Cyclophosphamide

Basiliximab

The answer is D. Cyclophosphamide has been successfully used for treatment of lupus nephritis; however, it does carry significant morbidity associated with its use. Azathioprine works by suppressing T-cell activity (A). Cyclosporine inhibits T-helper cell activation (B). Tacrolimus inhibits transcription of T-cell-specific lymphokines (C). Baciliximab is a monoclonal antibody against CD-25 used to reduce the incidence and severity of renal transplant rejection.

Explanation

The answer is D. Cyclophosphamide has been successfully used for treatment of lupus nephritis; however, it does carry significant morbidity associated with its use. Azathioprine works by suppressing T-cell activity (A). Cyclosporine inhibits T-helper cell activation (B). Tacrolimus inhibits transcription of T-cell-specific lymphokines (C). Baciliximab is a monoclonal antibody against CD-25 used to reduce the incidence and severity of renal transplant rejection.

19. Adverse effects seen with high blood levels of theophylline include

Seizures

Arrhythmias

Nervousness

Nausea and vomiting

All of the above

The answer is E. Theophylline is associated with all of the reactions listed. They usually occur at elevated blood levels, generally accepted as greater than 20 µg/dL. However, adverse drug reactions may occur at any blood level.

Explanation

The answer is E. Theophylline is associated with all of the reactions listed. They usually occur at elevated blood levels, generally accepted as greater than 20 µg/dL. However, adverse drug reactions may occur at any blood level.

20. Which of the following drugs is a selective α-adrenergic receptor agonist that is available over-the-counter?

Epinephrine

Phenylephrine

Isoproterenol

Norepinephrine

Phentolamine

The answer is B. Phenylephrine is a selective α1-adrenergic agonist that decreases nasal secretions by causing nasal vasoconstriction, decreasing the formation of such secretions. Epinephrine is the most potent of the adrenergic receptor agonists, followed by norepinephrine. Isoproterenol is the weakest antagonist. But the previous three agents also bind β-adrenergic receptors and are not available over the counter. Phentolamine is just the opposite, an α1-adrenergic antagonist.

Explanation

The answer is B. Phenylephrine is a selective α1-adrenergic agonist that decreases nasal secretions by causing nasal vasoconstriction, decreasing the formation of such secretions. Epinephrine is the most potent of the adrenergic receptor agonists, followed by norepinephrine. Isoproterenol is the weakest antagonist. But the previous three agents also bind β-adrenergic receptors and are not available over the counter. Phentolamine is just the opposite, an α1-adrenergic antagonist.

21. A 43-year-old high-profile attorney sees a psychiatrist with expertise in addiction medicine. He explains that he has recently received his third drunk driving citation and fears losing his license to practice unless he stops drinking altogether. He says he “just can't stop” once he starts. He tells the physician that he doesn't have time to attend Alcoholic Anonymous and “wants a pill.” The physician explains that there is something that might work if the patient is truly serious. What agent is the physician considering?

Lorazepam

Flumazenil

Naloxone

Disulfiram

Carbamazepine

The answer is D. Disulfiram is an inhibitor of aldehyde dehydrogenase, which blocks the breakdown of acetaldehyde to acetate during the metabolism of alcohol. The buildup of acetaldehyde results in flushing, tachycardia, hypertension and nausea to invoke a conditioned response to avoid alcohol ingestion. Lorazepam is useful in the prevention of seizures as a result of alcohol withdrawal, whereas carbamazepine is used should they develop. Flumazenil is used for benzodiazepine overdose and naloxone for opioid overdose.

Explanation

The answer is D. Disulfiram is an inhibitor of aldehyde dehydrogenase, which blocks the breakdown of acetaldehyde to acetate during the metabolism of alcohol. The buildup of acetaldehyde results in flushing, tachycardia, hypertension and nausea to invoke a conditioned response to avoid alcohol ingestion. Lorazepam is useful in the prevention of seizures as a result of alcohol withdrawal, whereas carbamazepine is used should they develop. Flumazenil is used for benzodiazepine overdose and naloxone for opioid overdose.

22. A 57-year-old male with a strong family history of Parkinson's disease sees a neurologist for an evaluation. On examination, the neurologist notes a slight pill-rolling tremor and subtle gait abnormalities. He begins treatment with levodopa, along with the addition of carbidopa. How does carbidopa work in this setting?

. Restores dopamine levels in the substantia nigra

Inhibits monoamine oxidase (MAOI)

Inhibits catechol-O-methyltransferase (COMT)

Functions as a dopamine agonist

Inhibits the metabolism of levodopa outside the CNS

The answer is E. Carbidopa, unlike levodopa, does not penetrate the CNS; it does inhibit levodopa's metabolism in the gut, leading to lower doses of levodopa and decreased side effects. Levodopa is a precursor to dopamine and can help restore levels of dopamine in the substantia nigra. Monoamine oxidase inhibitors should not be used with caution along with levodopa, as this can lead to a hypertensive crisis. Bromocriptine is a dopamine agonist used in the treatment of Parkinson's disease. COMT inhibitors are yet another class of agents used in the treatment of Parkinson's disease.

Explanation

The answer is E. Carbidopa, unlike levodopa, does not penetrate the CNS; it does inhibit levodopa's metabolism in the gut, leading to lower doses of levodopa and decreased side effects. Levodopa is a precursor to dopamine and can help restore levels of dopamine in the substantia nigra. Monoamine oxidase inhibitors should not be used with caution along with levodopa, as this can lead to a hypertensive crisis. Bromocriptine is a dopamine agonist used in the treatment of Parkinson's disease. COMT inhibitors are yet another class of agents used in the treatment of Parkinson's disease.

23. Dantrolene

Inhibits calcium release from the sarcoplasmic reticulum

Functions as a GABAB receptor agonist

Facilitates GABA activity in the CNS

Reactivates acetylcholinesterase

Competitively inhibits the effects of acetylcholine

The answer is A. Dantrolene is used in the treatment of malignant hyperthermia and works by inhibiting the release of calcium from the sarcoplasmic reticulum. Baclofen, an antispasmatic used in the treatment of multiple sclerosis, inhibits synaptic transmission as a GABAB-receptor agonist. Benzodiazepines function to facilitate GABA activity in the CNS and spinal cord. Pradoxime reactivates acetylcholinesterase. Nondepolarizing neuromuscular junction blockers such as atracurium competitively inhibit the effects of acetylcholine.

Explanation

The answer is A. Dantrolene is used in the treatment of malignant hyperthermia and works by inhibiting the release of calcium from the sarcoplasmic reticulum. Baclofen, an antispasmatic used in the treatment of multiple sclerosis, inhibits synaptic transmission as a GABAB-receptor agonist. Benzodiazepines function to facilitate GABA activity in the CNS and spinal cord. Pradoxime reactivates acetylcholinesterase. Nondepolarizing neuromuscular junction blockers such as atracurium competitively inhibit the effects of acetylcholine.

24. A 23-year-old female presents with hypertension, anxiety, and palpitations. Her thyroid-stimulating hormone levels are normal, but she has increased levels of urinary catecholamines. She is referred to a endocrine surgeon after a CT scan shows a unilateral pheochromocytoma. The surgeon should start therapy with which of the following agents prior to removing the lesion?

Dopamine

Phentolamine

. Pancuronium

Pseudoephedrine

Isoproterenol

The answer is B. An α-adrenergic blocker such as phentolamine is indicated for the treatment of pheochromocytomas in the preoperative state as well as if the tumor is inoperable. β-blockers are then used systemically, following effective α blockade, to prevent the cardiac effects of excessive catecholamines. Pseudoephedrine is an α -adrenergic antagonist available over the counter to relieve nasal discharge. There is no role for adrenergic receptor agonists such as dopamine or isoproterenol or for that matter nondepolarizing muscle relaxants such as pancuronium.

Explanation

The answer is B. An α-adrenergic blocker such as phentolamine is indicated for the treatment of pheochromocytomas in the preoperative state as well as if the tumor is inoperable. β-blockers are then used systemically, following effective α blockade, to prevent the cardiac effects of excessive catecholamines. Pseudoephedrine is an α -adrenergic antagonist available over the counter to relieve nasal discharge. There is no role for adrenergic receptor agonists such as dopamine or isoproterenol or for that matter nondepolarizing muscle relaxants such as pancuronium.

25. Vasopressin

Reduces ADH levels

Increases permeability of the collecting duct

Inserts aquaporins into the plasma membrane of collecting duct cells

Increases diffusion of sodium

Reduces production of prostaglandins

The answer is C. Vasopressin causes specific water channels termed aquaporins II to be inserted into the plasma membrane of the luminal surface of the medullary collecting ducts. This directly affects permeability of the collecting duct (choice B). Under the conditions of dehydration, as is the case with this patient, the ADH levels increase (choice A). Choice D represents the mechanism of action of osmotic diuretics. Production of prostaglandins is reduced with the use of agents such as indomethacin (choice E).

Explanation

The answer is C. Vasopressin causes specific water channels termed aquaporins II to be inserted into the plasma membrane of the luminal surface of the medullary collecting ducts. This directly affects permeability of the collecting duct (choice B). Under the conditions of dehydration, as is the case with this patient, the ADH levels increase (choice A). Choice D represents the mechanism of action of osmotic diuretics. Production of prostaglandins is reduced with the use of agents such as indomethacin (choice E).

26. A 32-year-old male complains of persistently dry cough for several days with a mild fever and fatigue. The family physician suspects a diagnosis of “walking pneumonia” on clinical grounds, presumably due to Mycoplasma pneumoniae. Which of the following groups of antibiotics would be effective?

Penicillins

Cephalosporins

Vancomycin

Chloramphenicol

Macrolides

The answer is E. Macrolides such as azithromycin or clarithromycin are the agents of choice for the treatment of mycoplasmal diseases. As mycoplasma have no cell wall, such drugs as penicillins, cephalosporins, or vancomycin are ineffective. Chloramphenicol is relatively toxic and reserved for select infections.

Explanation

The answer is E. Macrolides such as azithromycin or clarithromycin are the agents of choice for the treatment of mycoplasmal diseases. As mycoplasma have no cell wall, such drugs as penicillins, cephalosporins, or vancomycin are ineffective. Chloramphenicol is relatively toxic and reserved for select infections.

27. Which of the following is a side effect of clindamycin?

Dizziness

Bruising

Difficulty hearing

Diarrhea

Tendon pain

The answer is D. Diarrhea due to pseudomembranous colitis with Clostridium difficile overgrowth is common with many broad-spectrum antibiotics, especially clindamycin. Bruising can occur with some cephalosporins. Dizziness is common with tetracyclines such as minocycline. Ototoxicity can result in hearing loss with vancomycin and aminoglycosides. Tendon pain is possible due to the cartilage toxicity associated with fluoroquinolones.

Explanation

The answer is D. Diarrhea due to pseudomembranous colitis with Clostridium difficile overgrowth is common with many broad-spectrum antibiotics, especially clindamycin. Bruising can occur with some cephalosporins. Dizziness is common with tetracyclines such as minocycline. Ototoxicity can result in hearing loss with vancomycin and aminoglycosides. Tendon pain is possible due to the cartilage toxicity associated with fluoroquinolones.

28. A 54-year-old diabetic female was seen in the emergency room 3 weeks ago with complaints of swelling, warmth, and pain in her foot. She was diagnosed with cellulitis and sent home on a 10-day course of an oral first-generation cephalosporin. She returns with severe diarrhea, and Clostridium difficile is suspected. What is the initial treatment for this condition?

Clindamycin

Metronidazole

Ciprofloxacin

Neomycin

Silver sulfadiazine

The answer is B. Metronidazole is the preferred treatment for Clostridium difficile colitis, which probably resulted from the patient's use of a broad-spectrum antibiotic for her initial infection. Vancomycin is considered in the treatment of Clostridium difficile colitis in refractory cases. Clindamycin use is often associated with Clostridium difficile colitis. Ciprofloxacin can be used for the treatment of diverticulitis, but not colitis. Neomycin is used to sterilize the bowel, which is not the goal in this case. Silver sulfadiazine is used to treat skin infections in burn patients.

Explanation

The answer is B. Metronidazole is the preferred treatment for Clostridium difficile colitis, which probably resulted from the patient's use of a broad-spectrum antibiotic for her initial infection. Vancomycin is considered in the treatment of Clostridium difficile colitis in refractory cases. Clindamycin use is often associated with Clostridium difficile colitis. Ciprofloxacin can be used for the treatment of diverticulitis, but not colitis. Neomycin is used to sterilize the bowel, which is not the goal in this case. Silver sulfadiazine is used to treat skin infections in burn patients.

29. Which of the following is a short-acting acetylcholinesterase inhibitor?

Pyridostigmine

Bethanechol

Edrophonium

Scopolamine

Methantheline

The answer is C. In myasthenia gravis, autoantibodies develop to nicotinic acetylcholine receptors, causing impaired neuromuscular dysfunction that results in muscular fatigue. This fatigue can be treated with acetylcholinesterase inhibitors. Edrophonium is the shortest-acting agent in this class and used to diagnosis this disorder, with such weakness immediately corrected with its use. Pyridostigmine is a longer-acting agent used in the treatment of the disease. Bethanecol is a direct-acting muscarinic cholinergic agonist, whereas both scopolamine and methantheline are both muscarinic-receptor antagonists.

Explanation

The answer is C. In myasthenia gravis, autoantibodies develop to nicotinic acetylcholine receptors, causing impaired neuromuscular dysfunction that results in muscular fatigue. This fatigue can be treated with acetylcholinesterase inhibitors. Edrophonium is the shortest-acting agent in this class and used to diagnosis this disorder, with such weakness immediately corrected with its use. Pyridostigmine is a longer-acting agent used in the treatment of the disease. Bethanecol is a direct-acting muscarinic cholinergic agonist, whereas both scopolamine and methantheline are both muscarinic-receptor antagonists.

30. Which of the following is a good choice to treat newly diagnosed generalized anxiety disorder (GAD) in a patient who is a truck driver?

Alprazolam

Triazolam

Buspirone

Trazodone

Thiopental

The answer is C. Buspirone is a partial agonist of the 5-HT1A receptor that has efficacy comparable to that of benzodiazepines for the treatment of anxiety, although they are significantly less sedating. Alprazolam is an intermediate-acting benzodiazepine used in the treatment of GAD but still has some sedation, which would be undesirable in this situation. Triazolam is a short-acting benzodiazepine, and trazodone is a heterocyclic antidepressant, both used to induce sleep. Thiopental is a barbiturate sometimes used to induce anesthesia.

Explanation

The answer is C. Buspirone is a partial agonist of the 5-HT1A receptor that has efficacy comparable to that of benzodiazepines for the treatment of anxiety, although they are significantly less sedating. Alprazolam is an intermediate-acting benzodiazepine used in the treatment of GAD but still has some sedation, which would be undesirable in this situation. Triazolam is a short-acting benzodiazepine, and trazodone is a heterocyclic antidepressant, both used to induce sleep. Thiopental is a barbiturate sometimes used to induce anesthesia.

31. A 35-year-old intravenous drug abuser in a methadone maintenance program is admitted to the hospital for a work-up of suspected pulmonary tuberculosis. While in the hospital, he complains of diarrhea and cramping. After stool studies return with a negative result, you decide to begin an antidiarrheal. Which of the following is a good choice for this patient?

Kaolin

Codeine

Diphenoxylate

Loperamide

Propantheline

The answer is D. Loperamide would be a good choice in this patient as it effectively controls diarrhea. Both codeine and diphenoxylate are opioids with abuse potential, especially in patients with abusive histories. Diphenoxylate is available in combination with atropine to reduce the potential for abuse. Anticholinergics such as propantheline prevent cramping but have little effect on diarrhea. Kaolin is good for absorbing toxins from the intestines.

Explanation

The answer is D. Loperamide would be a good choice in this patient as it effectively controls diarrhea. Both codeine and diphenoxylate are opioids with abuse potential, especially in patients with abusive histories. Diphenoxylate is available in combination with atropine to reduce the potential for abuse. Anticholinergics such as propantheline prevent cramping but have little effect on diarrhea. Kaolin is good for absorbing toxins from the intestines.

32. A 7-year-old boy is brought to the neurologist by his mother. She says that the boy's teacher says there are times in class when he stares “out into space” and smacks his lips. In the office the boy has one such episode while having an EEG, which demonstrates a 3-per-second spike and wave tracing. Which drug is the best for this absence seizure?

Phenytoin

Carbamazepine

Prednisone

Lorazepam

Ethosuximide

The answer is E. Ethosuximide is the drug of choice for absence seizures in children. Valproic acid has more side effects and therefore is a second-line drug. Prednisone is used in infantile seizures. Phenytoin and carbamazepine can be used in partial seizures or in tonic-clonic seizures. Lorazepam is often used in the treatment of status epilepticus.

Explanation

The answer is E. Ethosuximide is the drug of choice for absence seizures in children. Valproic acid has more side effects and therefore is a second-line drug. Prednisone is used in infantile seizures. Phenytoin and carbamazepine can be used in partial seizures or in tonic-clonic seizures. Lorazepam is often used in the treatment of status epilepticus.

33. Which of the following is true regarding infliximab?

It is a recombinant antibody to TNF-α

It is a humanized antibody to TNF-α

It is a fusion protein that binds to TNF-α receptor

It is a recombinant protein resembling IL-1

It is a recombinant protein composed of a portion of LFA-3

The answer is A. Infliximab is a recombinant antibody to TNF-α it has been successfully used in the treatment of Crohn's disease, rheumatoid arthritis, and some other autoimmune conditions. Choice B represents Humira, an agent also used for rheumatoid arthritis. Choice C is Etanercept, a subcutaneous agent approved for treatment of rheumatoid arthritis. Choice D represents anakinra, an IL-1 blocker also used for rheumatoid arthritis. Choice E is alefacept, an agent used for psoriasis.

Explanation

The answer is A. Infliximab is a recombinant antibody to TNF-α it has been successfully used in the treatment of Crohn's disease, rheumatoid arthritis, and some other autoimmune conditions. Choice B represents Humira, an agent also used for rheumatoid arthritis. Choice C is Etanercept, a subcutaneous agent approved for treatment of rheumatoid arthritis. Choice D represents anakinra, an IL-1 blocker also used for rheumatoid arthritis. Choice E is alefacept, an agent used for psoriasis.

34. A 17-year-old male was placed on carbamazepine therapy by his neurologist to control newly developed seizures of unknown etiology. The patient was also recently given a macrolide antibiotic by his family physician for a presumed “walking pneumonia.” Halfway through his antibiotic course, the patient again developed seizures. What could account for this new seizure activity?

Inhibition of the cytochrome P-450 monooxygenase system

Induction of the cytochrome P-450 monooxygenase system

Impairment of renal excretion of the antiseizure medication

Induction of glucuronyl transferase activity in the liver

Reduction in the amount of nicotinamide adenine dinucleotide phosphate (NADPH)

1. The answer is B. Both carbamazepine and macrolide antibiotics are known inducers of the cytochrome P-450 system. Thus it is likely that the original therapeutic levels of antiseizure medicine was decreased to nontherapeutic levels when the metabolism of the drug was increased with the addition of the antibiotic. Some common drugs that inhibit P-450 include cimetidine, chloramphenicol, and disulfiram. Impaired renal excretion results in increased, not decreased, levels of drugs. The induction of glucuronyl transferase is a possible drug interaction, although less likely in this case. The P-450 system requires NADPH, and therefore a deficiency would result in decreased, not increased, activity by the system.

Explanation

1. The answer is B. Both carbamazepine and macrolide antibiotics are known inducers of the cytochrome P-450 system. Thus it is likely that the original therapeutic levels of antiseizure medicine was decreased to nontherapeutic levels when the metabolism of the drug was increased with the addition of the antibiotic. Some common drugs that inhibit P-450 include cimetidine, chloramphenicol, and disulfiram. Impaired renal excretion results in increased, not decreased, levels of drugs. The induction of glucuronyl transferase is a possible drug interaction, although less likely in this case. The P-450 system requires NADPH, and therefore a deficiency would result in decreased, not increased, activity by the system.

35. Which of the following is useful in an acute gout attack?

Probenecid

Sulfinpyrazone

Allopurinol

Colchicine

Celecoxib

The answer is D. Colchicine is often used to treat an acute gouty attack. Probenecid (A) and sulfinpyrazone (B) reduce urate levels by preventing reabsorption of uric acid. These agents are used for chronic gout. Allopurinol (C) is a xanthine oxidase inhibitor; it is also used for treatment of chronic gout. Celecoxib is a COX-2 inhibitor that has been removed from the market.

Explanation

The answer is D. Colchicine is often used to treat an acute gouty attack. Probenecid (A) and sulfinpyrazone (B) reduce urate levels by preventing reabsorption of uric acid. These agents are used for chronic gout. Allopurinol (C) is a xanthine oxidase inhibitor; it is also used for treatment of chronic gout. Celecoxib is a COX-2 inhibitor that has been removed from the market.

36. Chromosomal studies in a 56-year-old male indicate a (9:22) translocation, the Philadelphia chromosome, confirming the diagnosis of chronic myelocytic leukemia (CML). Which of the following might be used in his treatment?

Anastrozole

Rituximab

Imatinib

Gefitinib

Amifostine

The answer is C. Imatinib is an orally active small molecule inhibitor of the oncogenic bcr-abl kinase produced as a result of the Philadelphia chromosome, used to treat CML. It also inhibits the c-Kit receptor and can be used in gastrointestinal stromal tumors (GISTs). Anastrozole is used in the management of breast cancer. Rituximab is and antibody used in the treatment of non-Hodgkin's lymphoma. Gefitinib is an orally active small molecule inhibitor of the EGF receptor, used in the treatment of some lung cancer. Amifostine is used as a radio-protectant, with or without cisplatin.

Explanation

The answer is C. Imatinib is an orally active small molecule inhibitor of the oncogenic bcr-abl kinase produced as a result of the Philadelphia chromosome, used to treat CML. It also inhibits the c-Kit receptor and can be used in gastrointestinal stromal tumors (GISTs). Anastrozole is used in the management of breast cancer. Rituximab is and antibody used in the treatment of non-Hodgkin's lymphoma. Gefitinib is an orally active small molecule inhibitor of the EGF receptor, used in the treatment of some lung cancer. Amifostine is used as a radio-protectant, with or without cisplatin.

37. Which of the following would be a good option to help a patient fall asleep with minimal “hangover”?

Secobarbital

Zolpidem

Chlordiazepoxide

Flumazenil

Buspirone

The answer is B. Zolpidem has actions similar to those of benzodiazepines, although it is structurally unrelated. It is used as a hypnotic and anxiolytic with minimal abuse potential. Barbiturates such as secobarbital are rarely used because of their lethality on overdose. Chlordiazepoxide is a long-acting benzodiazepine, whereas most hypnotics are short-acting benzodiazepines. Flumazenil is a benzodiazepine antagonist that will not reverse the effects of zolpidem. Buspirone is not used as a hypnotic and has little sedative effect.

Explanation

The answer is B. Zolpidem has actions similar to those of benzodiazepines, although it is structurally unrelated. It is used as a hypnotic and anxiolytic with minimal abuse potential. Barbiturates such as secobarbital are rarely used because of their lethality on overdose. Chlordiazepoxide is a long-acting benzodiazepine, whereas most hypnotics are short-acting benzodiazepines. Flumazenil is a benzodiazepine antagonist that will not reverse the effects of zolpidem. Buspirone is not used as a hypnotic and has little sedative effect.

38. A 56-year-old female with severe rheumatoid arthritis returns to see her rheumatologist. She had been referred to a gastroenterologist, who had found multiple gastric ulcers on esophogastroduodenoscopy. She is reluctant to give up the use of NSAIDS and afraid of the potential cardiovascular toxicity of COX-2 inhibitor. At this point, what would be reasonable for the rheumatologist to prescribe?

Omeprazole

Lansoprazole

Nizatidine

Metronidazole

Misoprostol

The answer is E. Misoprostol is approved for use in patients taking NSAIDS, both to decrease acid production and to increase bicarbonate and mucous production. Both omeprazole and lansoprazole are proton inhibitors that would not increase the protective mucous and bicarbonate. Nizatidine is an H2-blocker that would also do nothing to increase the production of protective prostaglandins. Metronidazole is an antibiotic used to treat Helicobacter pylori.

Explanation

The answer is E. Misoprostol is approved for use in patients taking NSAIDS, both to decrease acid production and to increase bicarbonate and mucous production. Both omeprazole and lansoprazole are proton inhibitors that would not increase the protective mucous and bicarbonate. Nizatidine is an H2-blocker that would also do nothing to increase the production of protective prostaglandins. Metronidazole is an antibiotic used to treat Helicobacter pylori.

39. A 37-year-old female recently had a large soft tissue sarcoma surgically resected from her retroperitoneum. She is to receive both radiation and chemotherapy, with cyclophosphamide as part of her chemotherapy. Which agent should be given in conjunction with this drug?

MESNA

Allopurinol

Leucovorin

Cilastatin

MOPP

The answer is A. MESNA is often given with cyclophosphamide and ifosfamide to help detoxify metabolic products that can cause hemorrhagic cystitis. Allopurinol is given with chemotherapy agents such as busulfan to reduce renal precipitation of urate. Leucovorin is given to rescue patients in the case of methotrexate toxicity. Cilastatin is an inhibitor of imipenem degradation. MOPP is a multidrug regimen (Mechlorethamine, Oncovin (vincristine), Procarbazine, and Prednisone) used in the treatment of Hodgkin's disease.

Explanation

The answer is A. MESNA is often given with cyclophosphamide and ifosfamide to help detoxify metabolic products that can cause hemorrhagic cystitis. Allopurinol is given with chemotherapy agents such as busulfan to reduce renal precipitation of urate. Leucovorin is given to rescue patients in the case of methotrexate toxicity. Cilastatin is an inhibitor of imipenem degradation. MOPP is a multidrug regimen (Mechlorethamine, Oncovin (vincristine), Procarbazine, and Prednisone) used in the treatment of Hodgkin's disease.

40. A 54-year-old female is undergoing an experimental high-dose regimen with adriamycin and cyclophosphamide for breast cancer. As this treatment is particularly myelosuppressive, the oncologist is worried that her white blood cell count will drop dangerously low, making her susceptible to opportunistic infections. In addition to the chemotherapy, what is the oncologist likely to administer to prevent neutropenia?

Epoetin alpha

Filgrastim

Interferon-α

Oprelvekin

Amifostine

The answer is B. Filgrastim is a recombinant form of granulocyte colony-stimulating factor (G-CSF) given to prevent chemotherapy-induced neutropenia. Epoetin alpha is commonly used to prevent anemia while on chemotherapy. Oprelvekin is an agent used to help treat chemotherapy- induced thrombocytopenia. Interferon-α is used in the management of specific leukemias and lymphomas. Amifostine is given to patients receiving radiation to the head and neck to preserve salivary function.

Explanation

The answer is B. Filgrastim is a recombinant form of granulocyte colony-stimulating factor (G-CSF) given to prevent chemotherapy-induced neutropenia. Epoetin alpha is commonly used to prevent anemia while on chemotherapy. Oprelvekin is an agent used to help treat chemotherapy- induced thrombocytopenia. Interferon-α is used in the management of specific leukemias and lymphomas. Amifostine is given to patients receiving radiation to the head and neck to preserve salivary function.

41. Which of the following is a noncompetitive NMDA receptor inhibitor that can be used to treat Alzheimer's disease?

Memantine

Donepezil

Tacrine

Tolcapone

Pergolide

The answer is A. Memantine is an NMDA-receptor inhibitor that is well tolerated and shown to slow the rate of cognitive decline in Alzheimer's patients. Donepezil and tacrine are acetylcholinesterase inhibitors, which have shown similar activities. Tolcapone is a COMT inhibitor rarely used in Parkinson's disease because of the possibility of hepatic necrosis. Pergolide is an ergot derivative used as a dopamine agonist in the management of Parkinson's disease.

Explanation

The answer is A. Memantine is an NMDA-receptor inhibitor that is well tolerated and shown to slow the rate of cognitive decline in Alzheimer's patients. Donepezil and tacrine are acetylcholinesterase inhibitors, which have shown similar activities. Tolcapone is a COMT inhibitor rarely used in Parkinson's disease because of the possibility of hepatic necrosis. Pergolide is an ergot derivative used as a dopamine agonist in the management of Parkinson's disease.

42. A 21-year-old male sustains multiple blunt traumas after being beaten with a baseball bat by a gang. Aside from his fractures, a serum creatine kinase measurement is dramatically elevated and the trauma team is worried as the myoglobinuria caused by the trauma can cause kidney failure. They immediately begin to administer bicarbonate to alkalinize the urine. How does this serve to decrease myoglobin levels?

Increasing glomerular filtration

Promoting renal tubular secretion

Inhibiting renal tubular reabsorption

Increasing hepatic first-pass metabolism

Inducing the P-450 system

The answer is C. Alterations in urinary pH alters renal reabsorption of substances. In this case, alkalinization traps filtered myoglobin in the urine so that it cannot be reabsorbed, which leads to decreased levels in the serum. The other mechanisms such as increasing glomerular filtration, promoting tubular secretion are other potential ways to alter plasma drug/metabolite levels. Myoglobin is not hepatically metabolized; therefore, hepatic or P-450 metabolism would not alter myoglobin levels.

Explanation

The answer is C. Alterations in urinary pH alters renal reabsorption of substances. In this case, alkalinization traps filtered myoglobin in the urine so that it cannot be reabsorbed, which leads to decreased levels in the serum. The other mechanisms such as increasing glomerular filtration, promoting tubular secretion are other potential ways to alter plasma drug/metabolite levels. Myoglobin is not hepatically metabolized; therefore, hepatic or P-450 metabolism would not alter myoglobin levels.

43. Pilocarpine is what type of pharmacologic agent?

Indirect muscarinic agonist

α2-Adrenergic agonist

Carbonic anhydrase inhibitor

β-Adrenergic antagonist

Direct-acting muscarinic agonist

The answer is E. Pilocarpine is a direct-acting muscarinic agonist used in the management of acute narrow-angle glaucoma, often along with an indirect-acting muscarinic agonist like physostigmine. Carbonic anhydrase inhibiters (e.g., acetazolamide), β-adrenergic agonists, and even α2-adrenergic agonists can be used in the treatment of glaucoma.

Explanation

The answer is E. Pilocarpine is a direct-acting muscarinic agonist used in the management of acute narrow-angle glaucoma, often along with an indirect-acting muscarinic agonist like physostigmine. Carbonic anhydrase inhibiters (e.g., acetazolamide), β-adrenergic agonists, and even α2-adrenergic agonists can be used in the treatment of glaucoma.

44. A 5-year-old boy is brought to the emergency room by his parents after they found him with an empty bottle of aspirin. They are not sure how many tablets the boy consumed. On examination, the child is hyperpneic and lethargic. While the emergent treatment is started, a sample is drawn for an arterial blood determination. What pattern is most likely to be indicated by the arterial blood gas values?

Mixed metabolic alkalosis and respiratory alkalosis

Mixed respiratory alkalosis and metabolic acidosis

Mixed respiratory acidosis and metabolic acidosis

Mixed respiratory acidosis and metabolic alkalosis

Mixed metabolic acidosis and metabolic alkalosis

The answer is B. Salicylate toxicity initially increases the medullary response to carbon dioxide, with resulting hyperventilation and respiratory alkalosis. Increases in lactic acid and ketone body formation result in a metabolic acidosis. All other choices are incorrect in this particular setting. Treatment includes correction of acid—base disturbances, replacement of electrolytes and fluids, cooling, alkalinization of urine, and forced diuresis.

Explanation

The answer is B. Salicylate toxicity initially increases the medullary response to carbon dioxide, with resulting hyperventilation and respiratory alkalosis. Increases in lactic acid and ketone body formation result in a metabolic acidosis. All other choices are incorrect in this particular setting. Treatment includes correction of acid—base disturbances, replacement of electrolytes and fluids, cooling, alkalinization of urine, and forced diuresis.

45. AcA 45-year-old male with a 60-pack/year history of smoking presents to his primary care provider with loss of appetite, nausea, vomiting, and muscle weakness. His chest CT reveals enlarged hilar lymph nodes and a suspicious mass in the left hilar region. A presumptive diagnosis of lung cancer is made. Laboratory results reveal low levels of sodium, which in this setting has likely contributed to the syndrome of inappropriate ADH secretion. Which medication might be helpful for this patient's symptoms?

Clofibrate

Demeclocycline

Allopurinol

Acetazolamide

Furosemide

The answer is B. Demeclocycline is an ADH antagonist and as such is useful in treatment of SIADH, which is commonly seen in patients with lung cancer. Clofibrate (choice A) increases the release of ADH centrally. Allopurinol, acetazolamide, and furosemide do not affect actions of ADH to an appreciable degree (choices C, D, and E).

Explanation

The answer is B. Demeclocycline is an ADH antagonist and as such is useful in treatment of SIADH, which is commonly seen in patients with lung cancer. Clofibrate (choice A) increases the release of ADH centrally. Allopurinol, acetazolamide, and furosemide do not affect actions of ADH to an appreciable degree (choices C, D, and E).

46. Which of the following would be useful in the management of arrhythmia due to Wolf-Parkinson-White syndrome?

Digoxin

Lidocaine

Amiodarone

Adenosine

Atropine

The answer is D. Adenosine, a class V antiarrhythmic, is used for the treatment of paroxysmal supraventricular tachycardias, including those of Wolf-Parkinson-White syndrome. Digoxin (A) and amiodarone (C) can be used for management of atrial fibrillation. Lidocaine is used in treatment of many arrhythmias (B). Atropine is used for bradyarrhythmias.

Explanation

The answer is D. Adenosine, a class V antiarrhythmic, is used for the treatment of paroxysmal supraventricular tachycardias, including those of Wolf-Parkinson-White syndrome. Digoxin (A) and amiodarone (C) can be used for management of atrial fibrillation. Lidocaine is used in treatment of many arrhythmias (B). Atropine is used for bradyarrhythmias.

47. Soon after drug administration, the patient in the above question begins making odd faces with spastic movements of his neck. Which of the following should be administered to treat these dystonic reactions?

Fluphenazine

Bromocriptine

Dantrolene

Prolactin

Benztropine

The answer is E. Acute dystonias are a complication of antipsychotics that work primarily through dopamine D2 receptors and therefore have a high incidence of extrapyramidal effects. Haloperidol and agents such as fluphenazine are the most likely offenders. Such reactions are best managed with an anticholinergic such as benztropine. Another complication of haloperidol is the neuroleptic malignant syndrome, which is treated with the dopamine agonist bromocriptine as well as dantrolene. Hyperprolactinemia with galactorrhea is common with agents that block dopamine's actions, as dopamine normally represses prolactin release.

Explanation

The answer is E. Acute dystonias are a complication of antipsychotics that work primarily through dopamine D2 receptors and therefore have a high incidence of extrapyramidal effects. Haloperidol and agents such as fluphenazine are the most likely offenders. Such reactions are best managed with an anticholinergic such as benztropine. Another complication of haloperidol is the neuroleptic malignant syndrome, which is treated with the dopamine agonist bromocriptine as well as dantrolene. Hyperprolactinemia with galactorrhea is common with agents that block dopamine's actions, as dopamine normally represses prolactin release.

48. Risperidone works primarily through inhibition of receptors for

Dopamine

Serotonin

Histamine

Acetylcholine

Norepinephrine

The answer is B. The unique affinities of various antipsychotics result in their unique activities and their unique side effects. Risperidone is an atypical antipsychotic that works by blocking the 5-HT2A serotonin receptor. The older high-potency antipsychotics inhibit dopamine receptors. Agents such as clozapine inhibit histamine receptors. Chloropyramine has affinity for cholinergic as well as adrenergic receptors.

Explanation

The answer is B. The unique affinities of various antipsychotics result in their unique activities and their unique side effects. Risperidone is an atypical antipsychotic that works by blocking the 5-HT2A serotonin receptor. The older high-potency antipsychotics inhibit dopamine receptors. Agents such as clozapine inhibit histamine receptors. Chloropyramine has affinity for cholinergic as well as adrenergic receptors.

49. Which of the following agents is approved for treatment of diabetic neuropathy?

Phenytoin

Carbamazepine

Acetazolamide

Valproic acid

Gabapentin

The answer is E. Many antiseizure drugs find applications for other diseases. Gabapentin is approved for the treatment of diabetic nephropathy, an unfortunate consequence in this patient's presentation. Phenytoin is also used for the treatment of arrhythmias. Carbamazepine is used in the management of trigeminal neuralgia. Acetazolamide, sometimes used as an treatment for absence seizure control, is used in the treatment of glaucoma. Valproic acid can be used in the prophylaxis of migraine headaches.

Explanation

The answer is E. Many antiseizure drugs find applications for other diseases. Gabapentin is approved for the treatment of diabetic nephropathy, an unfortunate consequence in this patient's presentation. Phenytoin is also used for the treatment of arrhythmias. Carbamazepine is used in the management of trigeminal neuralgia. Acetazolamide, sometimes used as an treatment for absence seizure control, is used in the treatment of glaucoma. Valproic acid can be used in the prophylaxis of migraine headaches.

50. An 18-year-old African-American army recruit with a history of G-6-PDH deficiency is to be stationed in Somalia. During his tour of duty he develops a cyclic fever, malaise, and weakness. A thin blood smear shows malarial organisms within red blood cells. Which antimalarial is likely to give him the most hemolysis with use, given his enzyme deficiency?

Chloroquine

Pyrimethamine

Doxycycline

Primaquine

Sulfasalazine

The answer is D. Primaquine is associated with intravascular hemolysis or methemoglobinuria in G-6-PDH deficiency patients as it causes oxidative damage to hemoglobin. Chloroquine and pyrimethamine do not cause hemolysis, although they are often used with sulfa drugs, which can cause hemolysis in such patients. Chloroquine rarely causes hemolysis, and doxycycline is not known to cause problems in G-6-PDH deficiency.

Explanation

The answer is D. Primaquine is associated with intravascular hemolysis or methemoglobinuria in G-6-PDH deficiency patients as it causes oxidative damage to hemoglobin. Chloroquine and pyrimethamine do not cause hemolysis, although they are often used with sulfa drugs, which can cause hemolysis in such patients. Chloroquine rarely causes hemolysis, and doxycycline is not known to cause problems in G-6-PDH deficiency.

51. Which of the following might be considered for treatment of acute myelocytic anemia (M3 variant)?

Cisplatin

Lomustine

Tretinoin

Fluorouracil

Streptozocin

The answer is C. Tretinoin is all-trans-retinoic acid and produces remission by inducing differentiation in the M3 variant of AML, characterized by aberrant expression of a retinoic receptor-α gene. Cisplatin is often used in the treatment of cancers of the lung, head, and neck. Lomustine has good CNS penetration and is used in neuro-tumors. Fluorouracil is also used in multiple tumors including those of the breast and colon. Lastly, streptozocin is used in the treatment of insulinomas.

Explanation

The answer is C. Tretinoin is all-trans-retinoic acid and produces remission by inducing differentiation in the M3 variant of AML, characterized by aberrant expression of a retinoic receptor-α gene. Cisplatin is often used in the treatment of cancers of the lung, head, and neck. Lomustine has good CNS penetration and is used in neuro-tumors. Fluorouracil is also used in multiple tumors including those of the breast and colon. Lastly, streptozocin is used in the treatment of insulinomas.

52. Which of the following correctly describes the formula for a loading dose?

Loading dose = (Desired plasma concentration of drug) × (clearance)

Loading dose = (Clearance) × (Plasma drug concentration)

Loading dose = (0.693) × (Volume of distribution)/(Clearance)

Loading dose = (Amount of drug administered)/(Initial plasma concentration)

Loading dose = (Desired plasma concentration of the drug) × (Volume of distribution)

The answer is E. Loading dose = (Desired plasma concentration of the drug) × (Volume of distribution). The formula for the maintenance dose, once the loading dose is given, = (Desired plasma concentration of drug) × (Clearance). The elimination rate = (Clearance) × (Plasma drug concentration). The half-life of a drug = (Amount of drug administered)/(Initial plasma concentration). And lastly, the volume of distribution = (Amount of drug administered)/(Initial plasma concentration).

Explanation

The answer is E. Loading dose = (Desired plasma concentration of the drug) × (Volume of distribution). The formula for the maintenance dose, once the loading dose is given, = (Desired plasma concentration of drug) × (Clearance). The elimination rate = (Clearance) × (Plasma drug concentration). The half-life of a drug = (Amount of drug administered)/(Initial plasma concentration). And lastly, the volume of distribution = (Amount of drug administered)/(Initial plasma concentration).

53. A 45-year-old male with a history remarkable for both asthma and angina now has a kidney stone stuck in his right ureter. The urologist needs to perform cystoscopy, but the anesthesiologist is concerned about using a β-blocker during surgery to control the patient's blood pressure in light of his history of asthma. Ultimately, it is decide to use an ultra-short-acting β-blocker and closely monitor both his blood pressure and respiratory status. Which of the following is best to use in this situation?

Atenolol

Norepinephrine

Albuterol

Pseudoephedrine

Esmolol

The answer is E. Esmolol is an ultra-short-acting β1 antagonist that is relatively specific for
the heart; however, the short half-life of this drug should allow the anesthesiologist to fine tune the delivery and readily reverse the effects should there be problems with respiration. Atenolol is a much longer acting agent that would not provide such control. Norepinephrine would actually adversely affect the patient's angina, as it is stimulatory to the heart. Albuterol is a β agonist used in the treatment of asthma. Pseudoephedrine is an over-the-counter α agonist used in cold formula preparations.

Explanation

The answer is E. Esmolol is an ultra-short-acting β1 antagonist that is relatively specific for
the heart; however, the short half-life of this drug should allow the anesthesiologist to fine tune the delivery and readily reverse the effects should there be problems with respiration. Atenolol is a much longer acting agent that would not provide such control. Norepinephrine would actually adversely affect the patient's angina, as it is stimulatory to the heart. Albuterol is a β agonist used in the treatment of asthma. Pseudoephedrine is an over-the-counter α agonist used in cold formula preparations.

54. What is the mechanism of action of tacrolimus?

It inhibits transport to the nucleus of the transcription factor NF-AT

It stimulates apoptosis of some lymphoid lineages

It decreases the activity of calcineurin

It inhibits mTOR, which in turn delays the G1—S transition

It inhibits proliferation of promyelocytes

The answer is C. Tacrolimus decreases the activity of calcineurin, which leads to a decrease in nuclear NF-AT and the transcription of T-cell-specific lymphokines and early T-cell activation. Choice A refers to mechanism of action of cyclosporine. Choice B refers to glucocorticoids. Choice D represents the mechanism of action of sirolimus. Choice E refers to azathioprine.

Explanation

The answer is C. Tacrolimus decreases the activity of calcineurin, which leads to a decrease in nuclear NF-AT and the transcription of T-cell-specific lymphokines and early T-cell activation. Choice A refers to mechanism of action of cyclosporine. Choice B refers to glucocorticoids. Choice D represents the mechanism of action of sirolimus. Choice E refers to azathioprine.

55. The above patient returns for follow-up, and she still complains of bloody diarrhea, fever, and weight loss. The gastroenterologist has placed her on a trial of steroids, and yet she still complains of her symptoms. The gastroenterologist could consider using which of the following agents?

Infalyte

Opium tincture

Mesalamine

Infliximab

Diphenoxylate

The answer is D. Infliximab is a monoclonal antibody approved for the treatment of refractory Crohn's disease when mesalamine or steroids fail. Infalyte is an oral rehydration solution used in cases of childhood diarrhea. Opium tincture and diphenoxylate are opioid preparations for uncomplicated diarrhea.

Explanation

The answer is D. Infliximab is a monoclonal antibody approved for the treatment of refractory Crohn's disease when mesalamine or steroids fail. Infalyte is an oral rehydration solution used in cases of childhood diarrhea. Opium tincture and diphenoxylate are opioid preparations for uncomplicated diarrhea.

56. Which of the following can occur in a patient treated with chloramphenicol?

Gray baby syndrome

. Bone marrow suppression

Disulfiram-like reaction

Nephrotoxicity

Ototoxicity

The answer is B. Bone marrow suppression results in pancytopenia in treated patients, which in rare cases can lead to aplastic anemia. Gray baby syndrome is associated with chloramphenicol use in infants. Disulfiram-like reactions can occur with some cephalosporins. Aminoglycosides and vancomycin can result in nephrotoxicity and ototoxicity.

Explanation

The answer is B. Bone marrow suppression results in pancytopenia in treated patients, which in rare cases can lead to aplastic anemia. Gray baby syndrome is associated with chloramphenicol use in infants. Disulfiram-like reactions can occur with some cephalosporins. Aminoglycosides and vancomycin can result in nephrotoxicity and ototoxicity.

57. The patient in the previous question returns to see his neurologist 3 years later. At this time the patient's symptoms have progressed, and he now has marked bradykinesia and a profound shuffling gait. In an attempt to prevent further deterioration, the neurologist prescribes a catechol-O-methyltransferase (COMT) inhibitor on top of the patient's levodopa and carbidopa. Which agent below is likely to have been added?

Entacapone

Selegiline

Ropinirole

Amantadine

Benztropine

The answer is A. Levodopa is metabolized, in part by COMT; therefore, an inhibitor such as entacapone is an adjunct treatment for patients on levodopa. It does however increase the side effects including diarrhea, postural hypotension, nausea, and hallucinations. Selegiline is a MAOI used in the treatment of Parkinson's disease. Ropinirole is a nonergot dopamine agonist used in early Parkinson's disease that may decrease the need for levodopa in later stages of the disease. Amantadine has an effect on the rigidity of the disease as well as the bradykinesia, although it has no effect on the tremor. Benztropine is an antimuscarinic used as an adjunct drug in Parkinson's disease.

Explanation

The answer is A. Levodopa is metabolized, in part by COMT; therefore, an inhibitor such as entacapone is an adjunct treatment for patients on levodopa. It does however increase the side effects including diarrhea, postural hypotension, nausea, and hallucinations. Selegiline is a MAOI used in the treatment of Parkinson's disease. Ropinirole is a nonergot dopamine agonist used in early Parkinson's disease that may decrease the need for levodopa in later stages of the disease. Amantadine has an effect on the rigidity of the disease as well as the bradykinesia, although it has no effect on the tremor. Benztropine is an antimuscarinic used as an adjunct drug in Parkinson's disease.

58. A 32-year-old HIV-positive male follows up with an infectious disease (ID) specialist in the clinic. The results of his recent blood work suggest that the virus has become resistant to multiple nucleoside reverse transcriptase inhibitors. The ID specialist decides to include in the treatment a nonnucleoside inhibitor (nevirapine), which works by binding to a site near the active site on the reverse transcriptase. Nevirapine is an example of what?

Full agonist

Reversible competitive antagonist

Partial agonist

Noncompetitive antagonist

Irreversible competitive antagonist

The answer is D. By definition, drugs that do not bind to the active site, such as nonnucleotide reverse transcriptase inhibitors, are noncompetitive antagonists. They function by causing changes in the active site so that it cannot bind its native substrate. Agonists are drugs that elicit the same activity as the endogenous substrate, whereas partial agonists only induce some of the activities of the endogenous substrate. Competitive inhibitors, like nucleoside reverse transcriptase inhibitors, can be either reversible or irreversible.

Explanation

The answer is D. By definition, drugs that do not bind to the active site, such as nonnucleotide reverse transcriptase inhibitors, are noncompetitive antagonists. They function by causing changes in the active site so that it cannot bind its native substrate. Agonists are drugs that elicit the same activity as the endogenous substrate, whereas partial agonists only induce some of the activities of the endogenous substrate. Competitive inhibitors, like nucleoside reverse transcriptase inhibitors, can be either reversible or irreversible.

59. A 30-year-old patient is undergoing chemotherapy for Hodgkin's disease and develops a fever, prompting an admission by his oncologist. He is found to have a severely decreased white blood cell count and therapy is started with several antibiotics for febrile neutropenia. Assuming his regimen contains imipenem, which of the following must also be administered?

Probenecid

Clavulanic acid

Sulbactam

Cycloserine

Cilastatin

The answer is E. Cilastatin must be given with imipenem, and it is an inhibitor of renal dehydropeptidase, which normally would degrade imipenem. Probenecid increases penicillin concentrations by blocking their excretion by the kidney. Both clavulanic acid and sulbactam are penicillinase inhibitors used to increase the spectrum against penicillinase-producing species. Cycloserine is a second-line agent for gram-negative organisms and tuberculosis.

Explanation

The answer is E. Cilastatin must be given with imipenem, and it is an inhibitor of renal dehydropeptidase, which normally would degrade imipenem. Probenecid increases penicillin concentrations by blocking their excretion by the kidney. Both clavulanic acid and sulbactam are penicillinase inhibitors used to increase the spectrum against penicillinase-producing species. Cycloserine is a second-line agent for gram-negative organisms and tuberculosis.

60. A 23-year-old female, who is 23 weeks pregnant, develops a bladder infection due to Pseudomonas sp. As well, she has a documented allergy to penicillin. What might be the best choice, given the patient's history and condition?

Cefoxitin

Aztreonam

Imipenem

Piperacillin

Ciprofloxacin

The answer is B. Aztreonam is active against Pseudomonas spp., appears to be safe during pregnancy, and does not show cross-hypersensitivity with penicillins. Piperacillin, cefoxitin, and imipenem all have some overlap in penicillin-allergic patients. Although ciprofloxacin is good in nonpregnant patients, it is absolutely contraindicated in pregnancy.

Explanation

The answer is B. Aztreonam is active against Pseudomonas spp., appears to be safe during pregnancy, and does not show cross-hypersensitivity with penicillins. Piperacillin, cefoxitin, and imipenem all have some overlap in penicillin-allergic patients. Although ciprofloxacin is good in nonpregnant patients, it is absolutely contraindicated in pregnancy.

61. Trastuzumab works by

Inhibiting the oncoprotein bcr-abl

Blocking estrogen-mediated gene transcription

Preventing phosphorylation of a receptor tyrosine kinase

Targeting cells for destruction by antibody-mediated cellular cytotoxicity (ADCC)

Reducing circulating levels of tumor necrosis factor (TNF)

The answer is C. Trastuzumab is an antibody to the extracellular domain of the receptor tyrosine kinase HER2. In some breast cancers, HER2 is expressed in high levels leading to autophosphorylation in the absence of ligand binding. Trastuzumab blocks such signaling. Imatinib is used in chronic myelogenous leukemia (CML) and inhibits bcr-abl. Tamoxifen functions by inhibiting estrogen-mediated gene transcription. Rituximab targets CD20+ cells in B-cell lymphomas for ADCC. Thalidomide works in part by inhibiting TNF production.

Explanation

The answer is C. Trastuzumab is an antibody to the extracellular domain of the receptor tyrosine kinase HER2. In some breast cancers, HER2 is expressed in high levels leading to autophosphorylation in the absence of ligand binding. Trastuzumab blocks such signaling. Imatinib is used in chronic myelogenous leukemia (CML) and inhibits bcr-abl. Tamoxifen functions by inhibiting estrogen-mediated gene transcription. Rituximab targets CD20+ cells in B-cell lymphomas for ADCC. Thalidomide works in part by inhibiting TNF production.

62. A 37-year-old alcoholic is recovering from pneumonia due to Haemophilus influenzae in the hospital. His treatment included the use of intravenous antibiotics. The nurse calls you to evaluate the patient as he returned from a visit from his “buddy” outside. The nurse tells you he smells like alcohol and he is flush, warm, and uncomfortable. You suspect a disulfiram-like reaction. What antibiotic was he likely treated with?

Vancomycin

Bacitracin

Chloramphenicol

Isoniazid

Cefamandole

The answer is E. Cefamandole, a cephalosporin, is known to precipitate a disulfiram-like reaction. Bacitracin is not used IV, only topically. Chloramphenicol is associated with bone marrow suppression. Vancomycin can be associated with flush on infusion, the so-called red man syndrome. Isoniazid is an antituberculoid antibiotic.

Explanation

The answer is E. Cefamandole, a cephalosporin, is known to precipitate a disulfiram-like reaction. Bacitracin is not used IV, only topically. Chloramphenicol is associated with bone marrow suppression. Vancomycin can be associated with flush on infusion, the so-called red man syndrome. Isoniazid is an antituberculoid antibiotic.

63. Your resident asks you what the mechanism of action of tPA is. What is your answer?

It inhibits platelet aggregation

It increases antithrombin activity

It impairs inhibits fibrin polymerization

It blocks GPIIa/IIIb

It activates plasminogen bound to fibrin

The answer is E. As the name suggests, tPA activates plasminogen bound to plasmin, thereby acting as a thrombolytic. Choice A refers to clopidogrel and ticlopidine. Choice B refers to heparin and its analogues. Choice C refers to dextran. Finally, choice D refers to abciximab.

Explanation

The answer is E. As the name suggests, tPA activates plasminogen bound to plasmin, thereby acting as a thrombolytic. Choice A refers to clopidogrel and ticlopidine. Choice B refers to heparin and its analogues. Choice C refers to dextran. Finally, choice D refers to abciximab.

64. It is likely that the acquisition of antibiotic resistance in gram-negative bacilli such as vancomycin is a result of

Spontaneous mutation

Transformation

Transduction

Conjugation

Transposition

The answer is D. Conjugation is the principal mechanism for the acquisition of antibiotic resistance among enterobacteria and involves the transfer of resistance transfer factors on plasmids through sex pili. The other mechanisms for gene transfer, including random mutation, transformation, transduction, and transposition are not as common among these organisms.

Explanation

The answer is D. Conjugation is the principal mechanism for the acquisition of antibiotic resistance among enterobacteria and involves the transfer of resistance transfer factors on plasmids through sex pili. The other mechanisms for gene transfer, including random mutation, transformation, transduction, and transposition are not as common among these organisms.

65. A 29-year-old male who recently immigrated to the United States sees his physician for a burning sensation in his epigastrium. He is referred to a gastroenterologist, who performs esophogastroduodenoscopy with biopsy that demonstrate ulcers with the presence of Helicobacter pylori. Use of which of the following regimens would provide the most effective and shortest treatment?

Pepto Bismol, metronidazole, tetracycline, and omeprazole

Pepto Bismol, metronidazole, tetracycline, and ranitidine

Clathromycin, metronidazole, and omeprazole

Clathromycin, amoxicillin, and omeprazole

Pepto Bismol, metronidazole, and amoxicillin

The answer is A. Pepto Bismol, metronidazole, tetracycline, and omeprazole can be used for 7 days to eradicate Helicobacter pylori associated with peptic ulcer disease. Choice E (Pepto Bismol, metronidazole, and amoxicillin) was the original triple therapy. The use of a proton pump inhibitor is usually preferred to an H2-blocker, as in choice B. Regimens containing clathromycin are used for cases of resistance to metronidazole. All the choices except A require 14 days of treatment.

Explanation

The answer is A. Pepto Bismol, metronidazole, tetracycline, and omeprazole can be used for 7 days to eradicate Helicobacter pylori associated with peptic ulcer disease. Choice E (Pepto Bismol, metronidazole, and amoxicillin) was the original triple therapy. The use of a proton pump inhibitor is usually preferred to an H2-blocker, as in choice B. Regimens containing clathromycin are used for cases of resistance to metronidazole. All the choices except A require 14 days of treatment.

66. Which of the following would be an appropriate treatment to begin in a patient with Crohn's disease?

Glucocorticoids

Sulfasalazine

Bismuth subsalicylate

Octreotide

Loperamide

The answer is A. Glucocorticoids are used in the management of moderate cases of Crohn's disease. 5-Amino salicylic acid (5-ASA) compounds such as sulfasalazine are used in mild cases of ulcerative colitis. Octreotide is used for diarrhea secondary to increased release of gastrointestinal hormones. Bismuth subsalicylate and loperamide can be used in the treatment of uncomplicated diarrhea.

Explanation

The answer is A. Glucocorticoids are used in the management of moderate cases of Crohn's disease. 5-Amino salicylic acid (5-ASA) compounds such as sulfasalazine are used in mild cases of ulcerative colitis. Octreotide is used for diarrhea secondary to increased release of gastrointestinal hormones. Bismuth subsalicylate and loperamide can be used in the treatment of uncomplicated diarrhea.

67. A 17-year-old male presents with right lower quadrant pain with guarding and rebound. A CT scan demonstrates appendicitis, and he is taken to the operating room. What would be a good antibiotic to administer prophylactically before the surgery?

Cefazolin

Cefoxitin

Ceftriaxone

Aztreonam

Oxacillin

The answer is A. Cefazolin, a first-generation cephalosporin, is often used for surgical prophylaxis because it has activity against most gram-positive and some gram-negative organisms. Second-generation agents (cefoxitin) and third-generation agents (ceftriaxone) are not used because they have less gram-positive coverage. Aztreonam lacks activity against anaerobes and gram-positive organisms. Oxacillin is primarily active against staphylococci.

Explanation

The answer is A. Cefazolin, a first-generation cephalosporin, is often used for surgical prophylaxis because it has activity against most gram-positive and some gram-negative organisms. Second-generation agents (cefoxitin) and third-generation agents (ceftriaxone) are not used because they have less gram-positive coverage. Aztreonam lacks activity against anaerobes and gram-positive organisms. Oxacillin is primarily active against staphylococci.

68. A nonstimulant agent that can be used to treat attention-deficit/hyperactivity disorder (ADHD) is

Methylphenidate

Caffeine

Dextroamphetamine

Atomoxetine

Modafinil

The answer is D. Atomoxetine is a nonstimulant drug used in the management of ADHD that works by inhibiting norepinephrine reuptake. The stimulate agents used for the treatment of ADHD include methylphenidate and dextroamphetamine and work by inhibiting dopamine reuptake. Caffeine is a stimulant in many beverages, which may have some role in the management of some headaches. Modafinil is a newer agent used in the treatment of narcolepsy.

Explanation

The answer is D. Atomoxetine is a nonstimulant drug used in the management of ADHD that works by inhibiting norepinephrine reuptake. The stimulate agents used for the treatment of ADHD include methylphenidate and dextroamphetamine and work by inhibiting dopamine reuptake. Caffeine is a stimulant in many beverages, which may have some role in the management of some headaches. Modafinil is a newer agent used in the treatment of narcolepsy.

69. A 62-year-old female complains of severe back pain refractory to NSAID use. An x-ray film of the lumbar spine demonstrates “punched-out” lytic lesions. Her IgG levels are elevated and show a monoclonal spike. A bone marrow biopsy specimen showing malignant plasma cells confirms the diagnosis of multiple myeloma. In addition to chemotherapy, a bisphosphonate is started. Which of the following would be the best choice?

Plicamycin

Retinoic acid

Thalidomide

Zoledronic acid

Etidronate

The answer is D. Zoledronic acid is a powerful bisphosphonate given intravenously to treat patients with lytic lesions in multiple myeloma and bony metastases in breast and prostate cancer. Etidronate is a weak bisphosphonate that is orally active and used in the treatment of osteoporosis. Plicamycin is an antibiotic-type agent used to treat hypercalcemia associated with malignancy. Retinoic acid is used to treat acute myelocytic leukemia. Thalidomide is a unique agent used in the treatment of multiple myeloma.

Explanation

The answer is D. Zoledronic acid is a powerful bisphosphonate given intravenously to treat patients with lytic lesions in multiple myeloma and bony metastases in breast and prostate cancer. Etidronate is a weak bisphosphonate that is orally active and used in the treatment of osteoporosis. Plicamycin is an antibiotic-type agent used to treat hypercalcemia associated with malignancy. Retinoic acid is used to treat acute myelocytic leukemia. Thalidomide is a unique agent used in the treatment of multiple myeloma.

70. Tiagabine works by

Inhibiting GABA uptake by inhibiting the GABA transporter

Increasing GABA by stimulating its release from neurons

Increasing GABA-stimulated chloride channel opening

Prolonging GABA-induced channel opening

Blocking T-type calcium channels

The answer is A. Tiagabine is an anticonvulsant used in conjunction with drugs such as phenytoin. Its mechanism is related to its ability to inhibit GABA transport into the cell, thereby decreasing GABA uptake. Gabapentin works by stimulating the release of GABA from neurons. Benzodiazepines function to increase GABA-stimulated chloride channel opening, whereas barbiturates prolong GABA- induced chloride channel opening. Ethosuximide works by blocking T-type calcium channels.

Explanation

The answer is A. Tiagabine is an anticonvulsant used in conjunction with drugs such as phenytoin. Its mechanism is related to its ability to inhibit GABA transport into the cell, thereby decreasing GABA uptake. Gabapentin works by stimulating the release of GABA from neurons. Benzodiazepines function to increase GABA-stimulated chloride channel opening, whereas barbiturates prolong GABA- induced chloride channel opening. Ethosuximide works by blocking T-type calcium channels.

71. Which agent can be used to treat hairy cell leukemia?

Interferon-α

Interleukin-2

All-trans-retinoic acid

Rituximab

Daunorubicin

The answer is A. Interferon-α is used for the treatment of hairy cell leukemia, chronic myeloid leukemia, Kaposi's sarcoma, and lymphomas. Interleukin-2 is used in the treatment of metastatic renal cell carcinoma. All-trans-retinoic acid is used to induce remission in M3 AML. Rituximab is used to treat CD20+ non-Hodgkin's lymphoma (NHL). Daunorubicin is an antibiotic-type compound used in the treatment of some leukemias and lymphomas.

Explanation

The answer is A. Interferon-α is used for the treatment of hairy cell leukemia, chronic myeloid leukemia, Kaposi's sarcoma, and lymphomas. Interleukin-2 is used in the treatment of metastatic renal cell carcinoma. All-trans-retinoic acid is used to induce remission in M3 AML. Rituximab is used to treat CD20+ non-Hodgkin's lymphoma (NHL). Daunorubicin is an antibiotic-type compound used in the treatment of some leukemias and lymphomas.

72. Which of the following medications would provide the best relief from episodic attacks of Ménìre's disease?

Furosemide

Ondansetron

Diazepam

Emetrol

Phentermine

The answer is C. Diazepam and lorazepam are very effective at treating the vertigo associated with Ménìre's disease. Loop diuretics, such as furosemide, can precipitate vertigo secondary to volume depletion and resultant orthostatic hypotension. Ondansetron is a powerful antiemetic. Emetrol is an over-the-counter (OTC) antiemetic for infants. Phentermine is an amphetamine derivative that has been used for weight loss.

Explanation

The answer is C. Diazepam and lorazepam are very effective at treating the vertigo associated with Ménìre's disease. Loop diuretics, such as furosemide, can precipitate vertigo secondary to volume depletion and resultant orthostatic hypotension. Ondansetron is a powerful antiemetic. Emetrol is an over-the-counter (OTC) antiemetic for infants. Phentermine is an amphetamine derivative that has been used for weight loss.

73. A 62-year-old male alcoholic being treated for non-insulin-dependent diabetes mellitus comes to the emergency department with a 1-hour history of nausea, vomiting, headache, hypotension, and profuse sweating. What is the most likely causative agent?

Clomiphene

Glyburide

Chlorpropamide

Nandrolone

Vasopressin

The answer is C. A disulfiram-like reaction may be seen in non—insulin-dependent diabetics treated with chlorpropamide, an oral hypoglycemic, when used in combination with alcohol.

Explanation

The answer is C. A disulfiram-like reaction may be seen in non—insulin-dependent diabetics treated with chlorpropamide, an oral hypoglycemic, when used in combination with alcohol.

74. A 63-year-old female develops metastatic colon cancer. The pathologist confirms that a biopsy specimen retrieved from a recent colonoscopy demonstrates that the tumor overexpresses epidermal growth factor receptor (EGFR). The oncologist decides to add a monoclonal antibody to EGFR to her treatment. Which of the following would be added?

Rituximab

Erlotinib

Gefitinib

Cetuximab

Traztuzamab

The answer is D. Cetuximab inhibits the EGF receptor by binding to the extracellular domain of the receptor. Other EGFR signaling inhibitors include erlotinib and gefinitib, although both of these molecules are orally active and penetrate the cell to perturb EGFR signaling from within the cell. Rituximab and Traztuzamab are both antibodies as well, but are used in the treatment of non-Hodgkin's lymphoma and breast cancer, respectively.

Explanation

The answer is D. Cetuximab inhibits the EGF receptor by binding to the extracellular domain of the receptor. Other EGFR signaling inhibitors include erlotinib and gefinitib, although both of these molecules are orally active and penetrate the cell to perturb EGFR signaling from within the cell. Rituximab and Traztuzamab are both antibodies as well, but are used in the treatment of non-Hodgkin's lymphoma and breast cancer, respectively.

75. An 83-year-old male with multiple medical problems develops worsening constipation during his hospitalization for lower extremity cellulitis. The hospitalist decides to start giving a laxative. Which of the following is an appropriate choice and why?

Psyllium, because it is a bulk-forming laxative good for chronic constipation

An osmotic agent, such as senna, which is administered rectally

A stool softener such as lactulose administered rectally

A stool softener such as methyl cellulose that inhibits water reabsorption

A salt-containing osmotic agent such as docusate, useful in preventing constipation

The answer is A. Psyllium and methyl cellulose are bulk-forming agents good for chronic constipation. The osmotic agent lactulose is given orally. Stool softeners such as docusate are useful in preventing constipation. Salt-containing osmotic agents such as magnesium sulfate are good for acute evacuation of the bowels. Senna is an irritant agent that stimulates intestinal motility.

Explanation

The answer is A. Psyllium and methyl cellulose are bulk-forming agents good for chronic constipation. The osmotic agent lactulose is given orally. Stool softeners such as docusate are useful in preventing constipation. Salt-containing osmotic agents such as magnesium sulfate are good for acute evacuation of the bowels. Senna is an irritant agent that stimulates intestinal motility.