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• 1.

A drug given as a 100 mg single dose results in a peak plasma concentration of 20 ug/mL.  The apparent volume of distribution is (assume a rapid distribution and negligible elimination prior to measuring the peak plasma level):

• A.

0.5 L

• B.

1L

• C.

2L

• D.

5L

• E.

10L

D. 5L
Explanation
Vd=D/C, where D= the total amount of drug in the body and C=plasma concentration of drug. Thus Vd=100mg/20mg/mL=100/20mg/L= 5L.

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• 2.

A drug with a half life of 12 hours is administered by continuous intravenous infusion.  How long will it take for the drug to reach 90 percent of its final steady state level?

• A.

18 hours

• B.

24 hours

• C.

30 hours

• D.

40 hours

• E.

90 hours

D. 40 hours
Explanation
3.3 x t1/2= 3.3x12= about 40 hours

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• 3.

Which of the following results in a doubling of the steady state concentration of the drug?

• A.

Doubling the rate of infusion

• B.

• C.

Doubling the rate of infusion and doubling the concentration of the infused drug

• D.

Tripling the rate of infusion

• E.

A. Doubling the rate of infusion
Explanation
steady state is directly proportional to the infusion rate. INcreasing the loading dose provides a transient increase in drug level, but the steady state level remains unchanged. If you would double the rate and concnetration of infused drug you would quadruple the steady state drug concentration. Tripling or quadrupling the rate of infusion leads to either a 3 or 4 increase in the steady state concentration.

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• 4.

Heart failure patient shows dig toxicity.  She received 125 mcg as standard dose.  Serum levels were reported to be 2 ng/Ml.  Target therapeutic levels is 0.8 ng.  What dose should she receive?

• A.

25 mcg

• B.

50 mcg

• C.

75 mcg

• D.

100 mcg

B. 50 mcg
Explanation
The patient is experiencing digoxin toxicity, as their serum levels are higher than the target therapeutic levels. To reduce the risk of toxicity, the dose of digoxin should be decreased. The current dose is 125 mcg, and the serum level is 2 ng/Ml. The target therapeutic level is 0.8 ng. To achieve this target level, the dose should be reduced by half, resulting in a dose of 50 mcg.

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• 5.

The addition of the glucoronic acid to a drug

• A.

Decreases its water solubility

• B.

Usually leads to inactivation of the drug

• C.

Is an example of a Phase I reaction

• D.

Occurs at the same rate in adults and newborns

• E.

Involve cytochrome P450

B. Usually leads to inactivation of the drug
Explanation
Glucoronic acid prevents recognition of the drug by its receptor. GLucoronic acid is charged and the drug conjugate has increased water solubility. **Conjugation is a Phase II reaction. Neonates are deficient in conjugating enzymes. P450 is Phase I reactions.

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• 6.

Drug X produces maximal contraction of cardiac muscle in a similar manner similar to epinephrine.  Drug X is considered to be a

• A.

Agonist

• B.

Partial agonist

• C.

Competitive antagonist

• D.

Irreverisble antagonist

• E.

Inverse agonist

A. Agonist
Explanation
An agonist mimics actions of endogenous ligand. A partial agonist would only produce a partial effect. An antagonist would block or decrease its effects. An inverse agonist would reverse the constiutive activity of the receptors and exert the opposite pharmacologicla effect of receptor agonists.

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• 7.

Which of the following is correct?

• A.

If 10 mg of Drug A produces the same response as 100 mg of Drug B, Drug A is more efficacious than Drug B.

• B.

The greater the efficacy, the greater the potency of a drug.

• C.

IN selecting a drug, potency is usually more important than efficacy.

• D.

A competitive antagonist increases the ED50.

• E.

Variation in response to a drug among different individuals is most likely to occur with a drug showing a large therapeutic index.

D. A competitive antagonist increases the ED50.
Explanation
IN the presence of a competitive antagonist, a higher concentration of a drug is required to elicit a given response.

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• 8.

Variation in the sensitivity of a population of individuals to increasing doses of a drug is best determined by which of the following?

• A.

Efficacy

• B.

Potency

• C.

Therapeutic index

• D.

• E.

Quantal dose-response curve

E. Quantal dose-response curve
Explanation
A quantal dose-response curve is the best way to determine the variation in sensitivity of a population to increasing doses of a drug. This curve measures the proportion of individuals in a population that exhibits a specific response to different doses of the drug. By analyzing this curve, we can determine the range of doses at which individuals in the population start to show a response, as well as the variability in their response. This information helps in understanding the sensitivity of the population to the drug and identifying any outliers or subpopulations with different sensitivities.

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• 9.

Which of the following statements most accurately describes a system having spare receptors?

• A.

The number of spare receptors determines the maximum effect.

• B.

Spare receptors are sequestered in the cytosol.

• C.

A single drug-receptor interaction results in many cellular response elements being activated

• D.

Spare receptors are active even in the absensce of agonist.

• E.

Agonist affinity for spare receptors is less than their affinity for nonspare receptors.

C. A single drug-receptor interaction results in many cellular response elements being activated
Explanation
One explanation for the existence of spare receptors is that any on agonist receptor binding event can lead to activation of many more cellular response elements. Thus, only a small fraction of the receptors need to be bound to elicit a maximum cellular response.

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• 10.

Which one of the following statements concerning the parasympathetic nervous system is correct?

• A.

THe PNS uses norepinephrine as a neurotransmitter

• B.

The PNS often discharges as a single, functional system

• C.

The PNS division is involved in accomodation of near vision, movement of food and urination.

• D.

The postganglionic fibers of the PNS are long compared to those of the sympathetic nervous system

• E.

The PNS controls the secretion of the adrenal medulla.

C. The PNS division is involved in accomodation of near vision, movement of food and urination.
Explanation
The PNS maintains essential bodily functions, such as vision, movement of food and urination. It USES acetylcholine!!!!! and is discharges as discrete fibers that are activated separately. The postganglionic fibers of the PNS are short compared to those of sympathetic.

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• 11.

Which one of the following is characteristic of parasympathetic stimulation?

• A.

Decrease in intestinal motility

• B.

Inhibition of bronchial secretion

• C.

Contraction of sphincter muscle in the iris of the eye (miosis)

• D.

Contraction of sphincter of urinary bladder

• E.

Increase in heart rate

C. Contraction of sphincter muscle in the iris of the eye (miosis)
Explanation
PNS also does digestion and waste removal. Increase in heart rate is sympathetic nervous system. increased intestinal motility to facilitate peristalsis, relaxation of ruinary sphincter and increased bronchial secretions.

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• 12.

Which of the following is characteristic of the SNS?

• A.

Discrete response to activation

• B.

Actions mediated by muscarinic and nicotinic

• C.

Effects only mediated by norepi

• D.

Responses predominate during physical activity or when experiencing fright

• E.

Subjected to voluntary control

D. Responses predominate during physical activity or when experiencing fright
Explanation
SNS is fight or flight.

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• 13.

Patient presents with salivation, lacrimation, urination and defecation as side effects of a medication.  Which one of the following receptors mediates the actions of this drug?

• A.

Nicotoinic receptors

• B.

Alpha receptors

• C.

Muscarinic receptors

• D.

Beta receptors

C. Muscarinic receptors
Explanation
Muscarinic receptors of the PNS maintain essential body functions such as digestion and waste elimination. THe nicotinic receptors are recetpors for acetylcholline!!! It plays a major role in skeletal muscle, ganglia, etc. alpha and beta are recetpors for norepi and eli and activation of these receptors does not produce these effects.

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• 14.

A patient with an acute attack of glaucoma is treated with pilocarpine.  The primary reason for its effectiveness for this condition is:

• A.

Action to terminate acetylcholinesterase

• B.

Selectivity for nicotinic receptors

• C.

Ability to inhibit secretions, such as tears, saliva and sweat

• D.

Ability to lower intraocular pressure

• E.

Inability to enter the brain

D. Ability to lower intraocular pressure
Explanation
Pilocarpine can abort an acute attack of glaucoma because it causes pupillary constriction to lower intraocular pressure. It binds mainly to muscarinic receptors and can enter the brain. It is NOT effective in inhibiting secretions.

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• 15.

A soldiers unit has come under attack with a nerve agent.  The symptoms exhibited are skeletal muscle, paralysis, profuse bronchial secretions, miosis, bradycardia, and convulsions.  The alarm indicates exposure to an organophosphate.  What is the correct treatment?

• A.

Do nothing until you confirm the nature of the nerve agent

• B.

Administer atropine, and attempt to confirm the nature of the nerve agent

• C.

• D.

C. Adminsiter atropine and 2-PAM (pralidoxime)
Explanation
The correct treatment for exposure to an organophosphate, as indicated by the symptoms exhibited, is to administer atropine and 2-PAM (pralidoxime). Atropine helps to counteract the effects of the nerve agent by blocking the receptors in the body that the nerve agent targets. 2-PAM (pralidoxime) is an antidote that helps to reactivate the enzyme that the nerve agent inhibits, allowing the body to break down and eliminate the toxin. Administering both atropine and 2-PAM (pralidoxime) together is the most effective treatment in this case.

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• 16.

A patient on a diagnostic test for myasthenia gravis would be expected to have improved neuromuscular function after being treated wtih

• A.

Donepezil

• B.

Edrophonium

• C.

Atropine

• D.

Ecthothipohate

• E.

Neostigmine

B. Edrophonium
Explanation
Edrophonium is a short-acting cholinesterase inhibitor that can be used to diagnose myasthenia gravis. Myasthenia gravis is an autoimmune disorder that affects neuromuscular function, leading to muscle weakness and fatigue. Edrophonium works by blocking the breakdown of acetylcholine, a neurotransmitter that is responsible for transmitting signals between nerves and muscles. By inhibiting the breakdown of acetylcholine, edrophonium temporarily improves neuromuscular function in patients with myasthenia gravis. This improvement is typically seen within a few minutes after administration of edrophonium and can help confirm the diagnosis of myasthenia gravis.

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• 17.

The drug of choice for treating decreased salivation accompanying head and neck irradiation is

• A.

Physiostigmine

• B.

Scopolamine

• C.

Carbachol

• D.

Acetylcholine

• E.

Pilocarpine

E. Pilocarpine
Explanation
Pilocarpine is the drug of choice for treating decreased salivation accompanying head and neck irradiation. Pilocarpine is a cholinergic agonist that stimulates the secretion of saliva by activating muscarinic receptors in the salivary glands. It can effectively increase salivation in patients who have reduced salivary flow due to radiation therapy. Physiostigmine, scopolamine, carbachol, and acetylcholine are not specifically indicated for treating decreased salivation in this context.

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• 18.

A 75 year old man who was a smoker is diagnosed with COPD and suffers from occasional bronchospasm.  Which of the following would be effective in treating him?

• A.

Ipratropium bromide

• B.

Scopolamine patches

• C.

Mecamylamine

• D.

Oxygen

• E.

Nicotine

A. Ipratropium bromide
Explanation
This is the drug of choice, especially in a patient who can not tolerate an adrenergic agonist, which would dilate the bronchioles. Oxygen would improve aeration but not dilation.

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• 19.

Which of the following may precipitate an attack of open-angle glaucoma if instilled into the eye?

• A.

Physostigmine

• B.

Atropine

• C.

Pilocarpine

• D.

Echothiophate

• E.

Tropicamide

B. Atropine
Explanation
Atropine may precipitate an attack of open-angle glaucoma if instilled into the eye. Open-angle glaucoma is characterized by increased intraocular pressure, and atropine is known to cause pupil dilation and increase intraocular pressure. Therefore, the use of atropine in individuals with open-angle glaucoma can worsen the condition and potentially trigger an attack.

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• 20.

The prolonged apnea sometimes seen in patients who have undergone an operation in which succinylcholine was used as a muscle relaxant has been shown:

• A.

Urinary atony

• B.

Depressed levels of plasma cholinesterase

• C.

A mutation in acetylcholinesterase

• D.

A mutation in the nicotinic receptor at the NMJ

• E.

Weak histamine releasing action

B. Depressed levels of plasma cholinesterase
Explanation
Prolonged apnea after the use of succinylcholine as a muscle relaxant is a known side effect. This is due to the depressed levels of plasma cholinesterase, an enzyme responsible for metabolizing succinylcholine. When plasma cholinesterase levels are low, succinylcholine remains in the body for a longer period, leading to prolonged muscle relaxation and apnea. This explanation provides a clear understanding of the relationship between succinylcholine use, depressed levels of plasma cholinesterase, and the observed prolonged apnea.

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• 21.

A 50 yo male farm worker is brought to the ED.  He was found confused in the orchard and since then has lost consciousness.  His heart rate is 45, and his blood pressure is 80/44.  He is sweating and salivating profusely.  Which of the following treatments is indicated?

• A.

Physostigmine

• B.

Norepi

• C.

Trimethaphan

• D.

Atropine

• E.

Edrophonium

D. Atropine
Explanation
The patient's presentation of confusion, loss of consciousness, bradycardia, hypotension, and excessive sweating and salivation suggests that he is experiencing organophosphate poisoning. Atropine is the treatment of choice for organophosphate poisoning as it acts as an anticholinergic agent, blocking the effects of excessive acetylcholine release. It can help reverse the muscarinic effects of organophosphates, such as bradycardia, hypotension, and excessive secretions. Physostigmine, Norepinephrine (Norepi), Trimethaphan, and Edrophonium are not indicated in the treatment of organophosphate poisoning.

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• 22.

Nondepolarizing neuromuscular blockers are associated with all of the following except

• A.

Initial activation of AcH receptor and depolarization of the motor end plate

• B.

Effects are reversible by acetylcholinesterase inhibitors

• C.

Intermediate to long duration of action

• D.

Bind but do not activate AcH receptor

• E.

Most of these agents have minimal cardiovascular effects

A. Initial activation of AcH receptor and depolarization of the motor end plate
Explanation
Nondepolarizing neuromuscular blockers bind but do not activate the AcH receptor. This means that they block the action of AcH, preventing its activation of the receptor and subsequent depolarization of the motor end plate. The effects of nondepolarizing neuromuscular blockers can be reversed by acetylcholinesterase inhibitors, and they typically have an intermediate to long duration of action. Additionally, most of these agents have minimal cardiovascular effects.

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• 23.

A 68 year old man presents to the ED with acute heart failure.  THis patient requires immediate drug therapy to improve his cardiac function.  Which one of the following drugs would be most beneficial?

• A.

Albuterol

• B.

Dobutamine

• C.

Epi

• D.

Norepi

• E.

Phenylephrine

B. Dobutamine
Explanation
Dobutamine increases cardiac output without significantly increasing heart rate, a complicating condition in heart failure. Epi can significantly increase heart rate and is not typically used for acute heart failure.

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• 24.

Remedies for nasal stuffiness often contain which one of the following drugs?

• A.

Albuterol

• B.

Atropine

• C.

Epinephrine

• D.

Norepi

• E.

Phenylephrine

E. Phenylephrine
Explanation
THis is an alpha 1 agonist that constricts the nasal mucosa, thereby decreasing airway resistance

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• 25.

Which one of the following drugs, when administered intravenously, can decrease blood flow to the skin, increase blood flow to skeletal muscle, and increase the force and rate of cardiac contraction?

• A.

Epi

• B.

Isoproterenol

• C.

Norepi

• D.

Epi

• E.

Terbutaline

A. Epi
Explanation
Epinephrine (epi) is the correct answer. When administered intravenously, epinephrine can cause vasoconstriction in the skin, leading to a decrease in blood flow to the skin. At the same time, it can cause vasodilation in skeletal muscles, increasing blood flow to these muscles. Additionally, epinephrine can stimulate the heart, increasing the force and rate of cardiac contraction. Isoproterenol and norepinephrine have similar effects on cardiac contraction but do not specifically cause vasoconstriction in the skin. Terbutaline is a beta-2 adrenergic agonist that primarily affects smooth muscle relaxation.

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• 26.

The following circles represent pupillary diameter in one eye prior to and following the topical application of Drug X (insert control is small circle and drug X is larger circle).  Which of the following is most likely to be Drug X?

• A.

Physostigmine

• B.

Acetylcholine

• C.

Terbutaline

• D.

Phenylephrine

• E.

Isoproterenol

D. Phenylephrine
Explanation
The most likely answer to be Drug X is phenylephrine because it causes pupillary dilation. This can be inferred from the larger circle representing the pupillary diameter after the topical application of Drug X. Physostigmine and acetylcholine would cause pupillary constriction, terbutaline and isoproterenol would have no effect on pupillary diameter.

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• 27.

The graphs below depict the changes in blood pressure caused by the IV administration of epi before and after an unknown Drug X. <<insert>>  Which of the following is most likely Drug X?

• A.

Atropine

• B.

Phenylephrine

• C.

Physostigmine

• D.

Prazosin

• E.

Propranolol

D. Prazosin
Explanation
The correct answer is prazosin. Prazosin is a medication that belongs to the class of alpha-1 adrenergic blockers. It works by blocking the alpha-1 receptors in blood vessels, leading to vasodilation and a decrease in blood pressure. In the given scenario, the graphs depict a decrease in blood pressure after the administration of Drug X. This is consistent with the mechanism of action of prazosin, making it the most likely drug in this case.

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• 28.

A 38 yo male has recently started mono therapy for mild hypertension.  At his most recent office visit, he complains of tiredness and not being able to complete three sets of tennis.  Which one of the following drugs is he most likely to be taking for hypertension?

• A.

Albuterol

• B.

Atenolol

• C.

Ephedrine

• D.

Prazosin

B. Atenolol
Explanation
The most likely drug that the 38-year-old male is taking for hypertension is atenolol. Atenolol is a beta-blocker commonly used to treat high blood pressure. One of the side effects of beta-blockers is fatigue or tiredness, which aligns with the patient's complaint. Additionally, atenolol is not known to enhance athletic performance, so the patient's inability to complete three sets of tennis is consistent with this medication.

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• 29.

A 6o yo asthmatic man comes in for a checkup and complains that he is having some difficulty in "starting to urinate".  Physical exam indicates that the man has a BP of 160/100 and a slightly enlarged prostate.  Which of the following medications would be useful in treating both of these conditions?

• A.

Doxazosin

• B.

Labetalol

• C.

Phentolamine

• D.

Propranolol

A. Doxazosin
Explanation
Doxazosin is a medication that belongs to a class of drugs called alpha-1 blockers. It works by relaxing the muscles in the prostate and bladder neck, which helps to improve urine flow and reduce symptoms of an enlarged prostate. Additionally, doxazosin can also lower blood pressure by relaxing the blood vessels, making it a suitable choice for this patient who has both an enlarged prostate and high blood pressure. Labetalol, phentolamine, and propranolol are not indicated for the treatment of an enlarged prostate.

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• 30.

CJis having convulsions due to alcohol poisoning.  It is important that a quick therapeutic response is obtained with anticonvulsant medications.  Whch of the following routes of admin would provide the fastest therapeutic response?

• A.

Topical route

• B.

Transdermal

• C.

Subq

• D.

IV

• E.

Oral route

D. IV
Explanation
The intravenous (IV) route would provide the fastest therapeutic response in this situation. When a medication is administered intravenously, it is directly delivered into the bloodstream, allowing for rapid absorption and distribution throughout the body. This is especially important in cases of alcohol poisoning with convulsions, as prompt administration of anticonvulsant medications can help control seizures and prevent further complications. Topical, transdermal, subcutaneous, and oral routes would not provide the same level of immediate response as the IV route.

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• 31.

Drug showing zero order kinetics of elimination

• A.

Show a plot of drug concentration versus time that is linear

• B.

Decrease in concentration exponentially with time

• C.

Have a half life independent of dose

• D.

Are more common than those showing first order kinetics

• E.

Show a constant fraction of the drug eliminated per unit of time

A. Show a plot of drug concentration versus time that is linear
Explanation
A drug showing zero order kinetics of elimination will show a plot of drug concentration versus time that is linear. This means that the rate of elimination of the drug remains constant over time, resulting in a steady decrease in drug concentration. Unlike drugs that follow first order kinetics, the half-life of a drug exhibiting zero order kinetics is independent of the dose. Drugs that show zero order kinetics are less common than those showing first order kinetics, where a constant fraction of the drug is eliminated per unit of time.

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• 32.

Which one of the following is true for a drug whose elimination from plasma shows first order kinetics?

• A.

The amount eliminated per unit of time is constant

• B.

A plot of drug concentration versus time is a straight line

• C.

Elimination involve a rate limiting enzymatic reaction operating at its maximal velocity

• D.

The half life of the drug is proportional to the drug concentration in plasma

• E.

The rate of eliminaton is proportional to the plasma concentration

E. The rate of eliminaton is proportional to the plasma concentration
Explanation
For a drug with first-order kinetics, the rate of elimination is proportional to the plasma concentration. This means that as the concentration of the drug in the plasma decreases, the rate at which it is eliminated also decreases. Conversely, as the concentration increases, the rate of elimination increases. This relationship is characteristic of first-order kinetics, where the elimination process is not saturated and can occur at a constant rate.

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• 33.

Which one of the following statements is correct?

• A.

Coadmin of atropine speeds the absorption of a second drug

• B.

Drugs showing a large Vd can be efficiently removed by dialysis of the plasma

• C.

Weak bases are absorbed efficiently across the epithelial cells of the stomach

• D.

If the Vd of a drug is small most of the drug is in the extraplasmic space

• E.

Stressful emotions can lead to a slowing of drug absorption

E. Stressful emotions can lead to a slowing of drug absorption
Explanation
Stressful emotions can lead to a slowing of drug absorption. This is because during times of stress, the body's sympathetic nervous system is activated, leading to a decrease in blood flow to the gastrointestinal tract. This decrease in blood flow can result in a slower absorption of drugs taken orally.

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• 34.

A patient is treated with drug A, which has a high affinity for albumin and is administered in amounts that do not exceed the binding capacity of albumin.  A second drug, B, is added to the treatment regimen.  Durg B also has a high affinity for albumin but is adminsitered in amounts that are 100 times the binding capacity of albumin.  Which of the following occurs after administration of drug B?

• A.

A decrease in the tissue concentrations of drug A

• B.

An increase in the tissue concentrations of drug A

• C.

A decrase in the Vd of drug A

• D.

A decrease in the half life of drug A

• E.

Addition of more drug A significantly alters the serum concentration of unbound drug B

B. An increase in the tissue concentrations of drug A
Explanation
Drug B has a high affinity for albumin and is administered in amounts that are 100 times the binding capacity of albumin. This means that drug B will saturate albumin binding sites, preventing drug A from binding to albumin. As a result, there will be an increase in the unbound fraction of drug A, leading to an increase in the tissue concentrations of drug A.

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• 35.

Which of the following results in a doubling of the steady state concentration of a drug?

• A.

Tripling the rate of infusion

• B.

• C.

Doubling the rate of infusion

• D.

Doubling the rate of infusion and doubling the concentration

C. Doubling the rate of infusion
Explanation
Doubling the rate of infusion results in a doubling of the steady state concentration of a drug. This is because the steady state concentration of a drug is directly proportional to the rate of infusion. When the rate of infusion is doubled, more of the drug is being administered into the body per unit of time, leading to an increase in the steady state concentration of the drug.

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• 36.

Variation in the sensitivity of a population of individuals to increasing doses of a drug is best determined by which of the following?

• A.

Therpeutic index

• B.

Quantal dose response curve

• C.

Efficacy

• D.

Potency

• E.

B. Quantal dose response curve
Explanation
The quantal dose response curve is the best way to determine the variation in sensitivity of a population to increasing doses of a drug. This curve analyzes the proportion of individuals in a population that exhibit a specific response to different doses of a drug. By plotting the dose on the x-axis and the response on the y-axis, it allows for the identification of the threshold dose, the effective dose, and the lethal dose for a particular response. This curve provides valuable information about the range of responses within a population, helping to assess the sensitivity variations to the drug.

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• 37.

Drug X produces maximal contraction of cardiac muscle in a manner similar to epinephrine.  Drug X is considered to be a

• A.

Partial agonist

• B.

Agonist

• C.

Irreverisble antagonist

• D.

Inverse agonist

• E.

Competitive antagnist

B. Agonist
Explanation
Based on the given information, Drug X produces maximal contraction of cardiac muscle similar to epinephrine. An agonist is a substance that activates a receptor and produces a biological response. Since Drug X produces a similar effect to epinephrine, which is known to be an agonist, Drug X is also considered to be an agonist.

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• 38.

Which of the following most accurately describes a system having spare receptors?

• A.

The number of spare receptors determines the maximum effect

• B.

Agonist affinity for spare receptors is less than their affinitiy for nonspare receptors

• C.

Spare receptors are active even in the absence of agonist

• D.

Spare receptors are sequestered in the cytosol

• E.

A single drug receptor interaction results in many cellular response elements being activated

E. A single drug receptor interaction results in many cellular response elements being activated
Explanation
When a system has spare receptors, it means that there are more receptors available than necessary to produce a maximal response. In this case, a single drug receptor interaction can activate multiple cellular response elements, leading to a greater overall effect. This is because even though some receptors may not be bound by the drug, they are still active and can contribute to the cellular response. Therefore, the correct answer is that a single drug receptor interaction results in many cellular response elements being activated.

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• 39.

Which of the folllowing is correct?

• A.

Variation in response to a drug among different individuals is most likely to occur with a drug showing a large TI

• B.

The greater the efficacy, the greater the potency of a drug

• C.

A competitive antagonist increases the ED50

• D.

In selecting a drug, potency is usually more important than efficacy

C. A competitive antagonist increases the ED50
Explanation
A competitive antagonist increases the ED50. A competitive antagonist is a substance that competes with an agonist for binding to the same receptor site, thereby reducing the effectiveness of the agonist. By blocking the receptor, the antagonist increases the concentration of the agonist needed to produce a response, resulting in an increase in the effective dose (ED50) of the agonist. This means that a higher dose of the agonist is required to achieve the same effect in the presence of a competitive antagonist.

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• 40.

Acetylcholine is the NT mediating ganglionic transmission.  Which of the following receptors mediate aceylcholine effects at the autonomic ganglia?

• A.

Nicotinic receptors

• B.

Msucarinic receptors

• C.

Alpha receptors

• D.

Beta receptors

A. Nicotinic receptors
Explanation
Acetylcholine is the neurotransmitter that mediates ganglionic transmission in the autonomic nervous system. The receptors that mediate acetylcholine effects at the autonomic ganglia are nicotinic receptors. These receptors are named after nicotine, as they can be activated by nicotine and acetylcholine. Nicotinic receptors are ion channels that allow the flow of ions, such as sodium and potassium, across the cell membrane when acetylcholine binds to them. This activation leads to the transmission of signals between neurons in the autonomic ganglia, allowing for the regulation of various bodily functions.

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• 41.

Which of the following is characteristic of parasympathetic stimulation?

• A.

Contraction of the sphincter of the urinary bladder

• B.

Increase in heart rate

• C.

Inhibition of bronchial secretion

• D.

Decrease in intestinal motility

• E.

Contraction of sphincter muscle in the iris of the eye (miosis)

E. Contraction of sphincter muscle in the iris of the eye (miosis)
Explanation
Parasympathetic stimulation is known for its role in promoting rest and relaxation in the body. One characteristic of parasympathetic stimulation is the contraction of the sphincter muscle in the iris of the eye, which leads to miosis or constriction of the pupil. This response helps to reduce the amount of light entering the eye, allowing for better focus on nearby objects. The other options listed, such as contraction of the sphincter of the urinary bladder, inhibition of bronchial secretion, decrease in intestinal motility, and increase in heart rate, are all characteristics of sympathetic stimulation, which is associated with the "fight or flight" response.

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• 42.

Which one of the following statements concerning the parasympathetic nervous system is correct?

• A.

The para system often discharges as a single, functional system

• B.

The para system is involved in accomodation of near vision, movement of food and urination.

• C.

The postganglionic fibers of the para division are long compared to those of the sympathetic nervous system

• D.

The para system controls the secretion of the adrenal medulla

• E.

The para system uses norepi as a neurotransmitter

B. The para system is involved in accomodation of near vision, movement of food and urination.
Explanation
The correct answer is that the parasympathetic nervous system is involved in the accommodation of near vision, movement of food, and urination. This is because the parasympathetic system is responsible for rest and digest functions, which include controlling the contraction of the ciliary muscle for near vision accommodation, stimulating peristalsis for movement of food through the digestive system, and promoting the relaxation of the urinary bladder for urination.

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• 43.

A hiker is attacked by a grizzly bear.  Which of the following responses would be triggered by a sympathetic nervous system in response to the predator?

• A.

Miosis

• B.

Decrease in glucagon production

• C.

Bronchodilation

• D.

Increased motility of GI tract

• E.

Decrease heart rate

C. Bronchodilation
Explanation
When a hiker is attacked by a grizzly bear, the sympathetic nervous system is activated. This response is commonly known as the "fight or flight" response. Bronchodilation is one of the physiological responses triggered by the sympathetic nervous system in this situation. It involves the relaxation of the smooth muscles in the bronchioles, allowing for increased airflow to the lungs. This helps to improve oxygen intake and prepare the body for physical exertion or escape from the predator.

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• 44.

Which of the following is for the SNS?

• A.

Actions mediated by muscarinic and nicotinic receptors

• B.

Effects only mediated by norepi

• C.

Discrete response to activation

• D.

Responses predominate during physical activity or when experiencing fright

• E.

Subjected to voluntary control

D. Responses predominate during physical activity or when experiencing fright
Explanation
This answer refers to the sympathetic nervous system (SNS). The SNS is responsible for the "fight or flight" response, which is activated during physical activity or when experiencing fear or fright. This response includes increased heart rate, dilation of blood vessels, and release of adrenaline, among other physiological changes.

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• 45.

The drug of choice for treating decreased salivation accompanying head and neck irradiation is

• A.

Scopolamine

• B.

Acetylcholine

• C.

Physostigmine

• D.

Carbachol

• E.

Pilocarpine

E. Pilocarpine
Explanation
Pilocarpine is the drug of choice for treating decreased salivation accompanying head and neck irradiation. Pilocarpine is a cholinergic agonist that works by stimulating the muscarinic receptors in the salivary glands, increasing the production of saliva. This helps to alleviate the symptoms of dry mouth caused by radiation therapy. Scopolamine, acetylcholine, physostigmine, and carbachol are not typically used for this purpose.

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• 46.

A soldiers unit is under attack of a nerve agent.  The symptoms exhibited are skeletal muscle paralysis, profuse bronchial secretions, miosis, bradycardia and convulsions.  The alarm indicates exposure to an organophosphate.  What is the correct treatment?

• A.

• B.

Administer atropine, and attempt to confirm the nature of the nerve agent

• C.

• D.

Do nothing until you confirm

C. Adminsiter atropine and 2-PAM (praloxidime)
Explanation
The correct treatment for exposure to an organophosphate nerve agent is to administer atropine and 2-PAM (pralidoxime). Atropine helps to counteract the symptoms by blocking the effects of excessive acetylcholine in the body, while 2-PAM (pralidoxime) helps to reactivate the enzyme that breaks down the nerve agent. This combination of medications can help to alleviate the symptoms and improve the patient's condition. It is important to administer these treatments promptly to prevent further complications and minimize the effects of the nerve agent.

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• 47.

Drug used in diagnosis of myasthenia gravis

• A.

Edrophonium

• B.

Atropine

• C.

Bethanechol

• D.

Aceylcholine

A. Edrophonium
Explanation
Edrophonium is a drug used in the diagnosis of myasthenia gravis. Myasthenia gravis is an autoimmune disorder that affects the neuromuscular junction and leads to muscle weakness and fatigue. Edrophonium is a short-acting cholinesterase inhibitor that temporarily improves muscle strength in individuals with myasthenia gravis. It works by inhibiting the breakdown of acetylcholine, the neurotransmitter responsible for muscle contraction. By temporarily increasing acetylcholine levels, edrophonium can help confirm the diagnosis of myasthenia gravis by improving muscle strength in affected individuals. Atropine, bethanechol, and acetylcholine are not commonly used in the diagnosis of myasthenia gravis.

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• 48.

Patient presents with intraocular pressure increased due to narrow angle glaucoma.  Which of these can lower that pressure?

• A.

Atropine

• B.

Ipratropium bromide

• C.

Pilocarpine

• D.

Nicotine

C. Pilocarpine
Explanation
Pilocarpine can lower intraocular pressure in narrow angle glaucoma. It is a cholinergic agonist that acts on the ciliary muscle to cause constriction of the pupil and increase the outflow of aqueous humor, thereby reducing intraocular pressure. Atropine, ipratropium bromide, and nicotine do not have this effect and would not be effective in lowering intraocular pressure in this condition.

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• 49.

Postpartum female with atonic bladder.  Which of these can be used?

• A.

Atropine

• B.

Aceylcholine

• C.

Bethanecol

• D.

Scopolamine

C. Bethanecol
Explanation
Bethanecol can be used in the case of a postpartum female with atonic bladder. Bethanecol is a cholinergic agonist that stimulates the bladder muscles, helping to increase bladder tone and improve urinary retention. This medication can be beneficial in cases where the bladder is not contracting effectively, as in the case of atonic bladder. Atropine, acetylcholine, and scopolamine are not suitable options for this condition.

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• 50.

CJ is a farm worker that was found wandering in the orchards sffering from dry mouth, blurred vision, sandy eyes and tachycardia.  CJ admitted to having these sx after spraying the crop with insecticide.  Which of the following can be used to counteract the side effects?

• A.

Atropine

• B.

Nicotine

• C.

Physostigmine

• D.

Pancuronium

A. Atropine
Explanation
Atropine can be used to counteract the side effects experienced by CJ after spraying the crop with insecticide. Atropine is an anticholinergic medication that can help alleviate symptoms such as dry mouth, blurred vision, and tachycardia. It works by blocking the action of acetylcholine, a neurotransmitter involved in the transmission of nerve impulses. By inhibiting the effects of acetylcholine, atropine can help relieve the symptoms caused by excessive cholinergic activity, which may result from insecticide exposure. Nicotine, physostigmine, and pancuronium are not typically used to counteract the side effects of insecticide exposure.

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