31. Gastrointestinal and Antiemetic Drugs Flashcards
What are the main two causes of peptic ulcer disease?
Infection with Helicobacter pylori and use of NSAIDs.
What are the approaches to treating peptic ulcer disease?
Eradicating H. pylori infection, reduce gastric acid secretion with PPIs or H2 antagonists, protect gastric mucosa from damage.
What antimicrobials are used in H pylori eradication in peptic ulcer disease?
Amoxicillin, clarithromycin, metronidazole, tetracycline.
What H2-histamine receptor blockers are used in peptic ulcer disease management?
Cimetidine, famotidine, nizatidine, ranitidine.
What PPIs are used in peptic ulcer disease management?
Omeprazole, lansoprazole, esomeprazole.
Name a prostaglandin used in peptic ulcer disease management.
Misoprostol.
Name an antimuscarinic agent used in peptic ulcer disease management.
Dicyclomine.
What antacids are used in peptic ulcer disease management?
Aluminium hydroxide, calcium carbonate, magnesium hydroxide, sodium bicarbonate.
Which mucosal protective agents can be used in peptic ulcer disease management?
Bismuth subslicylate, sucralfate.
How is H pylori infection diagnosed?
Endoscopic biopsy of gastric mucosa, serology, or urea breath tests.
What is the triple therapy approach to H pylori eradication?
PPI + 2 x antibiotics (depends on hospital’s guidelines - amoxicillin + clarithromycin).
Which hormones stimulate gastric acid secretion?
Acetylcholine, histamine, and gastrin.
How do ACh, histamine, and gastrin stimulate gastric acid secretion?
Receptor mediated binding activates protein kinases which stimulate the H+/K+/ATPase to secrete hydrogen ions in exchange for K+ into the lumen of the stomach.
What is the action of H2 receptor antagonists?
Competitive antagonists of histamine, this is fully reversible.
What are the uses of H2 receptor antagonists?
Peptic ulcers, acute stress ulcers, GORD.
What are the ADRs of H2 antagonists?
Endocrine effects of cimetidine - gynaechomastia, galactorrhoea. CNS effects - confusion, altered mentation. Reduce efficacy of drugs that require an acidic environment for absorption.
What is the mechanism of action of PPIs?
Binds to H+/K+/ATPase so suppresses the secretion of hydrogen ions into gastric lumen.
What is Zollinger-Ellison syndrome?
Gastrin-producing tumour causes hypersecretion of HCl.