Deja Ch 8 GI Flashcards
What is the main cause of gastroesophageal reflux disease (GERD)?
Decreased lower esophageal sphincter pressure
What complications may arise from GERD?
Strictures; esophagitis; Barrett esophagus (squamocolumnar metaplasia)
What are the drug therapy goals in treating GERD?
To eliminate symptoms; heal esophagitis; prevent the relapse of esophagitis; prevent the development of complications
What types of medications may be useful in the treatment of GERD?
Antacids; H2-receptor antagonists; proton pump inhibitors (PPIs); prokinetic agents (cisapride, metoclopramide, bethanechol); mucosal protectants (sucralfate)
Give the mechanism of action for each of the following drugs or drug classes: Antacids
Weak bases that increase gastric pH through acid-neutralizing ability to form a salt and water
Give the mechanism of action for each of the following drugs or drug classes: H2–receptor antagonists
Competitively antagonize H2 receptors on gastric parietal cells, thereby decreasing acid production
Give the mechanism of action for each of the following drugs or drug classes: PPIs
Inhibit gastric acid secretion via inhibiting gastric parietal cell H+/K+-ATPase. Restoration of acid secretion requires resynthesis of the H+/K+-ATPase (proton pump).
Give the mechanism of action for each of the following drugs or drug classes: Cisapride
Increases lower esophageal sphincter pressure; accelerate gastric emptying time; increases amplitude of esophageal contractions; 5-HT4 agonist; 5-HT3antagonist
Give the mechanism of action for each of the following drugs or drug classes: Metoclopramide
Dopamine (D2) receptor antagonist; increases lower esophageal sphincter pressure; accelerates gastric emptying time
Give the mechanism of action for each of the following drugs or drug classes: Sucralfate
When exposed to acid, complexes with positively charged proteins to form a viscous coat, thereby protecting gastric lining from gastric acid secretions
What are the adverse effects caused by metoclopramide?
Anxiety; insomnia; extrapyramidal symptoms; increased prolactin levels
What are the adverse effects caused by sucralfate?
Constipation; nausea; abdominal discomfort
What are the possible adverse effects of antacids?
Belching (sodium bicarbonate and calcium carbonate); diarrhea (magnesium salts); constipation (calcium or aluminum salts); acid-base disturbances; bone damage via binding phosphate in the gut (aluminum salts); worsening of hypertension and congestive heart failure (CHF) (sodium salts); decreased absorption of medications via pH alteration or formation of insoluble complexes (tetracycline, fluoroquinolones, isoniazid [INH], ferrous sulfate, ketoconazole, PPIs)
Which antacid(s) can produce a metabolic alkalosis?
Sodium bicarbonate; calcium carbonate
What causes the milk-alkali syndrome?
Ingestion of excessive amounts of calcium and absorbable alkali such as sodium bicarbonate or calcium carbonate
What is a potential complication after discontinuing chronic antacid use?
Acid rebound
List the names of the H2-receptor antagonists:
Cimetidine; famotidine; ranitidine; nizatidine
Which H2-receptor antagonist inhibits hepatic cytochrome P-450 metabolizing enzymes?
Cimetidine
Name at least five drugs showing potential drug interactions with cimetidine:
- Warfarin 2. Diazepam 3. Phenytoin 4. Metronidazole 5. Propranolol 6. Lidocaine 7. Calcium channel blockers (CCBs) 8. Theophylline 9. Certain tricyclic antidepressants (TCAs); chlordiazepoxide
Which H2-receptor antagonist can cause gynecomastia?
Cimetidine (prolactin-stimulating activity)
Which H2-receptor antagonist has antiandrogenic activity?
Cimetidine
List the names of the PPIs:
Omeprazole; esomeprazole; lansoprazole; rabeprazole; pantoprazole
What are the common side effects of PPIs?
Headache; dizziness; nausea; diarrhea; constipation. Prolonged use can lead to bacterial overgrowth in the GI tract. Note also that a recent analysis revealed that people (age > 50) taking high doses of PPIs for more than a year were 2.6 times as likely to break a hip as were people not taking PPIs. Histamine H2-receptor inhibitors also increased fracture risk, but not to the extent as did PPIs.
What is the most serious side effect of cisapride?
Prolongation of the QT interval