Pharmacology - Problem Drill 21: Drugs Used To Treat GI Disorders No. 1 of 10 1. Endogenous secretagogues for stomach acid include: #01 (A) Histamine (B) Gastrin (C) PGE1 (D) A and B (E) A, B and C Histamine is a secretagogue for stomach acid, but this is not the only correct answer. Gastrin is a secretagogue for stomach acid, but this is not the only correct answer. PGE1 inhibits stomach acid secretion. D. Correct! Histamine and gastrin are both secretagogues for stomach acid. PGE1 inhibits stomach acid secretion. Acid is secreted from gastric parietal cells by a proton pump (K/H-ATPase). The three endogenous secretagogues for acid are histamine, acetylcholine and gastrin. PGE2 and PGE1 inhibit acid and stimulate mucus and bicarbonate secretion. The correct answer is (D).
No. 2 of 10 Instructions: (1) Read the problem and answer choices carefully (2) Work the problems on paper as needed (3) Pick the answer (4) Go back to review the core concept tutorial as needed. 2. Anatacids: #02 (A) Heal gastric ulcers (B) Heal duodoneal ulcers (C) Inhibit peptic activity (D) A and C (E) A, B and C Antacids heal gastric ulcers, but this is not their only action. B. Incrrect! Antacids do not heal duodoneal ulcers. Feedback on Each Answer Antacids inhibitr peptic activity, but this is not their only action. D. Correct! Antacids heal gastric ulcers and inhibit peptic activity. Antacids do not heal duodoneal ulcers. Antacids act by neutralizing acid and thus raise gastric ph. This has the effect of inhibiting peptic activity which practically ceases at ph 5. Given in sufficient quantity for long enough they can produce healing of gastric ulcers but not duodenal ulcers. The antacids commonly used include sodium bicarbonate, magnesium hydroxide and aluminum hydroxide. The correct answer is (D).
No. 3 of 10 3. is a rapid acting antacid, which acts by releasing carbon dioxide. #03 (A) Magnesium hydroxide (B) Sodium bicarbonate (C) Aluminum hydroxide (D) Colloidal aluminum hydroxide (E) Sucaralfate Magnesium hydroxide is an insoluble powder which reacts slowly with the gastric juice forming magnesium chloride in the stomach. B. Correct! Sodium bicarbonate is a rapid acting antacid, which acts by releasing carbon dioxide. Aluminum hydroxide gel forms aluminum chloride in the stomach, when this reaches the intestine the chloride is released and is reabsorbed. Colloidal aluminum hydroxide combines with phosphates in the GIT and the increased excretion of phosphate in the feces which occurs results in the decreased excretion of phosphate via the kidney. Sucralfate is a complex of aluminum hydroxide and sulphated sucrose which has been shown to promote the healing of ulcers. Sodium bicarbonate acts rapidly and is said to raise the ph of gastric juice to about 7.4. Carbon dioxide is liberated, which eradicates gas. This evolution of CO 2 stimulates gastrin secretion and can result in the secondary rise in acid secretion. Since some sodium bicarbonate is adsorbed in the intestine, large doses or frequent administration can cause alkalosis The correct answer is (B).
No. 4 of 10 4. Mucosal-protecting mechanisms include: #04 (A) Mucus (B) Bicarbonate (C) PGE1 (D) PGE2 (E) All of the above Mucus does protect the mucosal layer, but this is not the only correct answer. Bicarbonate does protect the mucosal layer, but this is not the only correct answer. PGE1 does protect the mucosal layer, but this is not the only correct answer. PGE2 does protect the mucosal layer, but this is not the only correct answer. E. Correct! Mucus-protecting mechanisms include mucus, bicarbonate, PGE1 and PGE2. Peptic ulcers are thought to be due to an imbalance between: Mucosal-damaging mechanisms (Acid, pepsin) and Mucosal-protecting mechanisms (mucus, bicarbonate, local synthesis of PGE1 and PGE2). The correct answer is (E).
No. 5 of 10 5. Agents that affect gastric secretion of acid include: #05 (A) Proton pump inhibitors (B) H2 receptor antagonists (C) Sucralfate (D) A and B (E) A, B and C Proton pump inhibitors reduce gastric secretion of acid, but this is not the only correct answer. H2 receptor antagonists reduce gastric secretion of acid, but this is not the only correct answer. Sucralfate stimulates mucus and bicarbonate secretion and prostaglandin production. D. Correct! Agents that affect gastric secretion of acid include proton pump inhibitors and H2 receptor antagonists. Sucralfate stimulates mucus and bicarbonate secretion and prostaglandin production. The two primary classes of drugs that affect gastric secretion are H2 receptor antagonists, including cimetidine, ranitidine, famotidine and nizatidine, and proton pump inhibitors. The correct answer is (D).
No. 6 of 10 6. Omeprazole is: #06 (A) Proton pump inhibitors (B) Antacids (C) PGE1 (D) Antibiotics (E) Motility stimulants A. Correct! Omeprazole is a proton pump inhibitor. Think of drugs that decrease acid production. Prostaglandin E1 is a protective mechanism. Think of drugs that decrease acid production. Think of drugs that decrease acid production. Proton Pump Inhibitors degrade rapidly at low ph; they are administered as capsules containing enteric-coated granules to prevent inactivation in the stomach. The class of drugs known as proton pump inhibitors includes: Omeprazole, Lansoprazole, Rabeprazole, Pantoprazole, and Esomeprazole. The correct answer is (A).
No. 7 of 10 as needed (3) Pick the answer (4) Go back to review the core concept tutorial as needed. 7. agents not only decrease both basal and food-stimulated acid secretion by 90% or more, but promote healing of duodenal ulcers. #07 (A) Proton pump inhibitors (B) Antacids (C) H2 receptor antagonists (D) Antibiotics (E) Motility stimulants Proton pump inhibitors should be taken on an empty stomach. Antacids do not heal duodoneal ulcers. C. Correct! H2 receptor antagonists not only decrease both basal and food-stimulated acid secretion by 90% or more, but promote healing of duodenal ulcers. Antibiotics do not affect gastric acid secretion. Motility stimulants do not affect gastric acid secretion. H2 receptor antagonists not only decrease both basal and food-stimulated acid secretion by 90% or more, but promote healing of duodenal ulcers, as shown by numerous clinical trials. Relapses are likely to follow when treatment with H2- receptor antagonists is stopped. The correct answer is (C).
No. 8 of 10 8. Sucralfate: #08 (A) Stimulates the mucosal protecting mechanisms. (B) Promotes the healing of ulcers. (C) Is a complex of aluminum hydroxide and sulphated sucrose. (D) A and C (E) A, B and C Sucralfate stimulates the mucosal protecting mechanisms, but this is not its only action. Sucralfate promotes the healing of ulcers, but this is not its only action. Sucralfate is a complex of aluminum hydroxide and sulphated sucrose, but this is not its only characteristic. More than just A and C are correct. E. Correct! Sucralfate stimulates the mucosal protecting mechanisms, promotes the healing of ulcers and is a complex of aluminum hydroxide and sulphated sucrose. Sucralfate is a complex of aluminum hydroxide and sulphated sucrose which has been shown to promote the healing of ulcers. In the presence of acid, sucralfate releases aluminum, acquires a strong negative charge and binds to positively charged groups in proteins, glycoproteins etc. It adheres to both damaged normal mucosa. It can form complex gels with mucus, and action which is thought to decrease the degradation of mucus by pepsin and to limit the diffusion of hydrogen ions. It stimulates the mucosal protecting mechanisms- mucus and bicarbonate secretion and prostaglandin production. The correct answer is (E).
No. 9 of 10 9. Misoprostol is a stable analogue for: #09 (A) Histamine (B) Gastrin (C) PGE1 (D) A and B (E) A, B and C Think of an inhibitor of gastric acid secretion. Think of an inhibitor of gastric acid secretion. C. Correct! Misoprostol is a stable analogue for prostaglandin E1. Think of an inhibitor of gastric acid secretion. Think of an inhibitor of gastric acid secretion. Misoprostol is a stable analogue for prostaglandin E1. It inhibits gastric acid secretion both basal and that occurring in response to food, histamine, pentagastrin and caffeine by a direct action on the parietal cell. It maintains or increases mucosal blood flow and increases the secretion of mucus and bicarbonate. The correct answer is (C).
No. 10 of 10 as needed (3) Pick the answer (4) Go back to review the core concept tutorial as needed. 10. Domperidone acts at: #10 (A) D1 dopamine receptors. (B) D2 dopamine receptors. (C) H1 histamine receptors. (D) H2 histamine receptors. (E) Serotonin receptors. Think of a different dopamine receptor. B. Correct! Domperidone is a dopamine receptor antagonist acting at D2-receptors and is used as an anti-emetic. Try one of the dopamine receptors. Try one of the dopamine receptors. Try one of the dopamine receptors. Domperidone is a dopamine receptor antagonist acting at D2-receptors and is used as an anti-emetic. It is also effective in increasing gastrointestinal motility. Clinically it increases lower esophageal sphincter pressure, increases gastric emptying and enhances duodenal peristalsis. It does not stimulate gastric acid secretion. It is useful in disorders of gastric emptying and in chronic gastric reflux. The correct answer is (B).