Block 14 Pharm GI Drugs Prt 3

1. A 43-year-old woman is referred to a gastroenterologist by her primary care physician after she complains of burning stomach pain for 3 weeks accompanied by intermittent indigestion and bloating, and produces a negative guiaic test. The patient undergoes an upper endoscopy which reveals a 0.5 cm ulcer in the duodenal bulb without evidence of active bleeding. A biopsy of the area tests positive for Helicobacter pylori. The patient is started on a 14 day triple drug regimen consisting of clarithromycin, amoxicillin, and what other drug?

Calcium carbonate

Sucralfate

Cimetidine

Lubiprostone

Infliximab

Omeprazole

F is the correct answer. The 14-day triple therapy regimen consists of clarithromycin, amoxicillin/metronidazole, and a proton pump inhibitor.

Explanation

F is the correct answer. The 14-day triple therapy regimen consists of clarithromycin, amoxicillin/metronidazole, and a proton pump inhibitor.

2. A 55-year-old man with a history of gastric ulcer presents to the hospital with a persistent epigastric pain in spite of 12 weeks of ranitidine treatment. After an endoscopy which shows a partially healed gastric ulcer, a diagnosis of refractory ulcer is made. Biopsy results are positive for Helicobacter pylori. Which of the following drug combination would represent the best treatment for this patient?

Amoxicillin, sucralfate, and magnesium hydroxide

Famotidine and magnesium hydroxide

Omeprazole, famotidine, and tetracycline

Metronidazole and sucralfate

Omeprazole, metronidazole, and clarithromycin

E is the correct answer. The best drug regimens for treatment of H. pylori-associated ulcers are the combination of antibiotics with a proton pump inhibitor.

Explanation

E is the correct answer. The best drug regimens for treatment of H. pylori-associated ulcers are the combination of antibiotics with a proton pump inhibitor.

3. A 62-year-old man with newly diagnosed lung cancer is scheduled to receive his first course of chemotherapy. A prophylactic antiemetic medication is planned. A drug from which of the following classes would be most appropriate for this patient?

Serotonergic antagonists

Dopaminergic agonist

Muscarinic antagonists

Gabaergic agonists

Adrenergic agonists

A is the correct answer. Ondansetron and its family members are the primary go-to drugs for the prevention of acute chemotherapy-induced nausea and vomiting.

Explanation

A is the correct answer. Ondansetron and its family members are the primary go-to drugs for the prevention of acute chemotherapy-induced nausea and vomiting.

4. A 67-year-old man comes to the clinic complaining of nervousness, anxiety, insomnia, palpitation, and stomach pain. He has been suffering from COPD for 15 years which is presently treated with inhaled albuterol and ipratropium, and oral theophylline. He told the attending physician that he recently started taking cimetidine for an acid stomach. Which of the following statements best describes the mechanism of the patient's current complains?

Cimetidine increased the clearance of theophylline

Cimetidine decreased the clearance of theophylline

Cimetidine increased the clearance of albuterol

Theophylline increased the clearance of cimetidine

Theophylline decreased the clearance of cimetidine

B is the correct answer. Cimetidine is a potent inhibitor of the cytochrome P450 enzyme system, which can inhibit the metabolism of numerous drugs, including their metabolic clearance.

Explanation

B is the correct answer. Cimetidine is a potent inhibitor of the cytochrome P450 enzyme system, which can inhibit the metabolism of numerous drugs, including their metabolic clearance.

5. A 45-year-old man, recently diagnosed with duodenal ulcer, started a treatment with antacids and omeprazole. Which of the following statements best describes the mechanism of action of antacids in peptic ulcer disease?

They inhibit the gastric secretion of hydrochloric acid and pepsins

They stimulate the secretion of bicarbonate by epithelial cells

They react with hydrochloric acid to form a salt and water

They bind to necrotic ulcer tissue, so acting as a barrier for acid and pepsin

They stimulate the secretion of prostaglandin PGE2.

C is the correct answer. Antacids function as Brønsted bases by accepting the proton from gastric hydrochloric acid.

Explanation

C is the correct answer. Antacids function as Brønsted bases by accepting the proton from gastric hydrochloric acid.

6. A 61-year-old man comes to the hospital for evaluation of his continuing ulcers. He has been treated for one year for peptic ulcer and has not experienced relief, despite escalating doses of various H2-receptor antagonists. All routine laboratory tests are within normal limits except a serum gastrin level, which is 3240 pm/mL (normal 0-100). Radiographic and endoscopic studies demonstrate one gastric and two duodenal ulcers. A drug with which of the following mechanisms of action would be most appropriate for this patient?

Blockade of H2-receptors of gastric parietal cells

Activation of EP3 receptors of gastric epithelial cells

Coating the gastric ulcer craters

Neutralization of hydrochloric acid in the stomach lumen

Inhibition of H+/K+ ATPase of gastric parietal cells

E is the correct answer. Proton pump inhibitors are the current mainstay of treatment for peptic ulcer disease, and are an excellent choice in a patient who has not experienced relief using H2-receptor antagonists.

Explanation

E is the correct answer. Proton pump inhibitors are the current mainstay of treatment for peptic ulcer disease, and are an excellent choice in a patient who has not experienced relief using H2-receptor antagonists.

7. A 23-year-old woman suffering with chronic constipation begins self-medicating with a therapeutic agent that functions by absorbing water in the GI tract leading to the formation of a bulky emollient gel which promotes peristalsis. Which of the following drugs is the patient most likely using to treat her symptoms?

Docusate

Lactulose

Balanced polyethylene glycol

Methylcellulose

Senna

Mineral oil

Lubiprostone

D is the correct answer. Methylcellulose is a bulk-forming laxative, a group of agents that possess this mechanism of action. Docusate is a stool surfactant agent (permits water and lipids to penetrate stool). Mineral oil is also a stool surfactant (lubricates fecal material, preventing water loss from the stool). Lactulose and balanced polyethylene glycol are osmotic laxatives (increase stool liquidity by increasing fecal fluid content). Senna is a stimulant laxative (directly stimulates ENS function). Lubiprostone stimulates type 2 chloride channels in the small intestine.

Explanation

D is the correct answer. Methylcellulose is a bulk-forming laxative, a group of agents that possess this mechanism of action. Docusate is a stool surfactant agent (permits water and lipids to penetrate stool). Mineral oil is also a stool surfactant (lubricates fecal material, preventing water loss from the stool). Lactulose and balanced polyethylene glycol are osmotic laxatives (increase stool liquidity by increasing fecal fluid content). Senna is a stimulant laxative (directly stimulates ENS function). Lubiprostone stimulates type 2 chloride channels in the small intestine.

8. A 44-year-old man has been recently diagnosed with a duodenal ulcer and an antiulcer treatment was prescribed. Four weeks into therapy the patient complained of difficulty in erection during sex. He also noticed a bilateral enlargement of his breast. Which of the following drugs was most likely prescribed?

Famotidine

Omeprazole

Sucralfate

Cimetidine

Bismuth subsalicylate

Misoprostol

D is the correct answer. Cimetidine has inhibitory action on the androgen receptor, which can lead to both impotence and gynecomastia in men.

Explanation

D is the correct answer. Cimetidine has inhibitory action on the androgen receptor, which can lead to both impotence and gynecomastia in men.

9. A 75-year-old man with terminal metastatic lung cancer has been in the hospital for 4 months. Recently his renal function has deteriorated and now laboratory results show creatinine 5.5 mg/dL and BUN 45 mg/dL. Because of poor food intake, immobility, and requirement for opioid analgesia, the patient is severely constipated and needs daily laxative therapy. Which of the following would be a suitable laxative for this patient?

Lactulose

Alosetron

Magnesium hydroxide

Sodium phosphate

Fosaprepitant

A is the correct answer. C and D are contraindicated because of potential adverse effects that they can cause in patients with renal impairment. B and E are not laxatives.

Explanation

A is the correct answer. C and D are contraindicated because of potential adverse effects that they can cause in patients with renal impairment. B and E are not laxatives.

10. A 55-year-old man suffering with severe Crohn disease is unresponsive to conventional therapy and is prescribed infliximab. After 4 weeks of therapy, the patient displays excellent symptomatic improvement. What is the mechanism of action of this agent?

Neutralizing the a4 subunit of integrin

Neutralizing soluble and membrane-bound tumor necrosis factor

Directly modifying the gene expression of pro-inflammatory cells

Inhibiting the production of prostaglandins and leukotrienes

Blocking the conversion of folic acid into active metabolites

Inhibiting de novo synthesis of purine nucleotides

B is the correct answer. Infliximab is a monoclonal antibody that binds and neutralizes both soluble and membrane-bound TNF molecules.

Explanation

B is the correct answer. Infliximab is a monoclonal antibody that binds and neutralizes both soluble and membrane-bound TNF molecules.

11. A 42-year-old man, who has been receiving his first course of chemotherapy for a non-Hodgkin's lymphoma, still complains of recurrent nausea and vomiting despite an antiemetic medication with ondansetron, dexamethasone, and aprepitant. Which of the following drugs would be appropriate to add to the patient's antiemetic regimen?

Famotidine

Omeprazole

Loperamide

Dronabinol

Triamcinolone

Meclizine

D is the correct answer. The patient has failed to respond to a 5-HT3-receptor antagonist, a glucocorticoid, and a NK1-receptor antagonist. Dronabinol is indicated for the prevention of chemotherapy-induced nausea and vomiting.

Explanation

D is the correct answer. The patient has failed to respond to a 5-HT3-receptor antagonist, a glucocorticoid, and a NK1-receptor antagonist. Dronabinol is indicated for the prevention of chemotherapy-induced nausea and vomiting.

12. A 25-year old female is planning to take a 2-week cruise aboard a small sailboat. She has a history of motion sickness. A drug from which of the following classes would be most appropriate to prevent nausea and vomiting in this patient?

Serotonergic antagonists

Glucocorticoids

Muscarinic agonists

Gabaergic agonists

H1- receptor antagonists

Dopaminergic agonist

E is the correct answer. The 1st generation H1-receptor antagonists are the drugs of choice for the prevention and treatment of motion sickness.

Explanation

E is the correct answer. The 1st generation H1-receptor antagonists are the drugs of choice for the prevention and treatment of motion sickness.

13. A 38-year-old woman is scheduled to undergo a GI endoscopic procedure. The night before the patient is administered bisacodyl and another drug to promote complete colonic cleansing before the procedure is performed. Which of the following drugs was most likely the additional pharmacological agent given to this patient to facilitate this clinical outcome?

Methylcellulose

Lubiprostone

Alvimopan

Lactulose

Docusate

Balanced polyethylene glycol

F is the correct answer. Balanced polyethylene glycol is utilized for this clinical purpose, often in conjunction with bisacodyl.

Explanation

F is the correct answer. Balanced polyethylene glycol is utilized for this clinical purpose, often in conjunction with bisacodyl.

14. 36-year-old man reports to the emergency department with signs and symptoms consistent with a tuberculosis infection and laboratory investigations confirm this diagnosis. The patient had been successfully treated for tuberculosis in the past and was in a state of remission. Within the past three months, the man had been started on a new therapeutic agent for the treatment of his worsening Crohn disease. Which of the following drugs did the patient most likely just have added to his drug regimen?

Mesalamine

Dicyclomine

Aprepitant

Diphenoxylate

Metoclopramide

Infliximab

F is the correct answer. While all immunosuppressive agents can theoretical predispose a patient to infection, infliximab appears to be one of the primary GI agents associated with the risk of the development of tuberculosis. This potential is so significant that all patients should be prescreened for tuberculosis using PPD testing, and those with a positive result should be put on prophylactic antituberculosis therapy when beginning treatment with infliximab.

Explanation

F is the correct answer. While all immunosuppressive agents can theoretical predispose a patient to infection, infliximab appears to be one of the primary GI agents associated with the risk of the development of tuberculosis. This potential is so significant that all patients should be prescreened for tuberculosis using PPD testing, and those with a positive result should be put on prophylactic antituberculosis therapy when beginning treatment with infliximab.

15. A 29-year-old man reports to a general practitioner complaining of nausea and vomiting, fatigue, confusion, and a "hazy feeling" in his head. The patient's history reveals that he is an avid consumer of milk and cheese and a frequent user of over-the-counter (OTC) medications to treat heartburn and sour stomach. Laboratory investigations reveal a serum Ca2+ level of 12.3 mg/dL (normal: 8.4-10.2). The physician determines that the patient's condition is resulting from his excessive use of OTC drugs. Which of the following types of drugs is the patient most likely suffering adverse effects to?

Antacids

H2-receptor antagonists

Proton pump inhibitors

Bismuth-containing agents

Prostaglandins

Bulk-forming laxatives

Aminosalicylates

A is the correct answer. The patient is most likely suffering from milk-alkali syndrome, which can result from excessive doses of sodium bicarbonate or calcium carbonate, especially if they are taken in conjunction with intake of calcium-containing dairy products.

Explanation

A is the correct answer. The patient is most likely suffering from milk-alkali syndrome, which can result from excessive doses of sodium bicarbonate or calcium carbonate, especially if they are taken in conjunction with intake of calcium-containing dairy products.

16. A 47-year-old woman with a history of opioid dependence is prescribed loperamide to treat the frequent diarrhea associated with her chronic ulcerative colitis. Why is this drug a good choice in this patient?

Antagonizes opioid receptors

Mimics the pharmacological effects of somatostatin

Does not increase fecal water absorption

Displays poor distribution in the CNS

Inhibits gastric H+/K+ ATPase

D is the correct answer. Loperamide is an opioid, but displays poor distribution in the CNS. Thus, the risk of the patient becoming dependent on this agent is relatively low.

Explanation

D is the correct answer. Loperamide is an opioid, but displays poor distribution in the CNS. Thus, the risk of the patient becoming dependent on this agent is relatively low.

17. A 55-year-old man is brought to the emergency department because of significant hematemesis and passing of melena for the past 2 hrs. The patient's wife reports that her husband has no significant past medical history and that he has been a daily alcohol drinker for the past 15-years. Physical examination results include: BP 78/40 mmHg Pulse 110 bpm Respirations 22/min Chest/Cardiac Within normal limits Abdomen Ascites, palpable spleen, normal bowel sounds Laboratory work is performed with the following results: Hgb 7 g/dL (normal 13.5-17.5) Hct 27% (normal 41-53) AST 160 U/L (normal 8-20) ALT 250 U/L (normal 8-20) Alkaline phosphatase 40 U/L (normal 20-70) An ECG reveals sinus tachycardia. The patient is transfused with three units of whole blood and two units of fresh frozen plasma. Gastric lavage with saline was performed and gastric aspirate from the nasogastric tube was strongly positive for blood. The patient is prepped for immediate endoscopy in order to determine the source of the bleeding. In the meantime, the physician orders the parenteral administration of a drug that will help to treat the patient's suspected condition. What is the mechanism of action of the pharmacological agent that was most likely administered to this patient?

Inhibition of serotonin 5-HT3 receptors

Stimulation of somatostatin receptors

Neutralization of soluble and membrane-bound TNF-a

Regulation of target cell gene expression

Antagonism of peripheral u-opioid receptors

B is the correct answer. The patient is suffering from bleeding esophageal varices, which demands emergency therapy with octreotide. This drug functions as a somatostatin receptor agonist.

Explanation

B is the correct answer. The patient is suffering from bleeding esophageal varices, which demands emergency therapy with octreotide. This drug functions as a somatostatin receptor agonist.

18. A 24-year-old woman complains to her gastroenterologist of chronic constipation. The patient was diagnosed with IBS six months previously. The physician prescribes a drug that functions by stimulating the action of small intestine type 2 chloride channels. Which of the following agents was prescribed to the patient?

Methylnaltrexone

Ursodiol

Docusate

Lubiprostone

Bisacodyl

D is the correct answer. Lubiprostone is a laxative that utilizes this mechanism of action.

Explanation

D is the correct answer. Lubiprostone is a laxative that utilizes this mechanism of action.

19. A 42-year-old man recently diagnosed with peptic ulcers and GERD has started self-medicating with ranitidine. What is the mechanism of action of this pharmacological agent?

Irreversible inhibition of H+/K+ ATPase

Reaction with gastric HCl to form a salt and water

Competitive inhibition of histamine H2-receptors

Irreversible inhibition of histamine H2-receptors

Competitive inhibition of H+/K+ ATPase

Forms a physical barrier over ulcers and luminal erosions

C is the correct answer. Ranitidine is a H2-receptor antagonist.

Explanation

C is the correct answer. Ranitidine is a H2-receptor antagonist.

20. A 37-year-old woman recently diagnosed with irritable bowel syndrome complains to her gastroenterologist of nausea, bloating, pain, and frequent severe diarrhea that has proven to be unresponsive to the use of loperamide. The physician prescribes alosetron and it significantly reduces all of her IBS-related symptoms. Which of the following statements correctly identifies why alosetron is effective at reducing the patient's incidence of diarrhea?

Stimulation of colonic motility

Enteric cholinergic neuron 5-HT3-receptor inhibition

Afferent GI neuron 5-HT3-receptor activation

Decrease of total colonic transit time

Central 5-HT3-receptor antagonism

Enhancement of the central response to visceral afferent stimulation

B is the correct answer. Serotonin antagonism in the ENS by alosetron causes inhibition of colonic motility and increases total colonic transit time, thus making it effective at reducing diarrhea. It does the opposite of A, C, D, and F. Its central action is responsible for its ability to reduce the central response to visceral afferent stimulation.

Explanation

B is the correct answer. Serotonin antagonism in the ENS by alosetron causes inhibition of colonic motility and increases total colonic transit time, thus making it effective at reducing diarrhea. It does the opposite of A, C, D, and F. Its central action is responsible for its ability to reduce the central response to visceral afferent stimulation.

21. A 55-year-old man ,suffering from type II diabetes for 15 years, presented with a 2-month history of nausea, postprandial fullness, and uncomfortable bloating, all of which are unrelieved by antacids. The patient also had manifestation of autonomic neuropathy (impotence and orthostatic hypotension). A preliminary diagnosis of diabetic gastroparesis was confirmed later by physical examination and lab results. Which of the following drugs would be suitable to treat this patient's gastrointestinal symptoms?

Ondansetron

Loperamide

Metoclopramide

Dronabinol

Omeprazole

Bisacodyl

C is the correct answer. Metoclopramide is a prokinetic drug that is indicated for the therapy of delayed gastric emptying resulting from diabetic gastroparesis.

Explanation

C is the correct answer. Metoclopramide is a prokinetic drug that is indicated for the therapy of delayed gastric emptying resulting from diabetic gastroparesis.

22. A 46-year-old man undergoes Beger's resection to remove the head of his pancreas in order to treat his worsening chronic pancreatitis. A nasoenteric feeding tube is temporarily inserted while the patient recovers in the hospital. In order to facilitate the advancement of the tube from the patient's stomach into the duodenum, which of the following drugs was administered to the patient?

Metoclopramide

Famotidine

Erythromycin

Alvimopan

Natalizumab

Pancrelipase

A is the correct answer. Metoclopramide is a prokinetic drug utilized for this clinical purpose.

Explanation

A is the correct answer. Metoclopramide is a prokinetic drug utilized for this clinical purpose.