GI drugs Flashcards
What is the mechanism of PPI?
Inhibit gastric acid secretion by blocking proton pump of gastric parietal cells.
What is omeprazole used for?
GORD, peptic ulcer disease, dyspepsia (indigestion), H. pylori infection
Common side effects of PPI?
Abdominal pain, dizziness, dry mouth.
What are the cautions of using PPI?
PPIS can mask symptoms of gastric cancer, long term use in the elderly can increase risk of fractures. (Patients at risk of osteoporosis should maintain intake of calcium and vitamin D)
What are the different types of laxatives?
Osmotic laxatives - draw fluid out tissues and into colonic lumen.
Stimulatory laxatives - stimulate colon to contract more
Bulk forming laxatives - attracts water into stool to bulk it to stimulate peristalsis
What is ispaghula husk (fybogel) and methylcellulose an example of and used for what?
Bulk forming laxative for constipation and faecal impaction.
What laxative would you use to manage hepatic encephalopathy?
Osmotic laxative e.g. lactulose
What is phosphate enema and lactulose an example of?
Osmotic laxative used for hepatic encephalopathy, constipation and faecal impaction.
What is senna and bisacodyl a example of and used for what?
Stimulant laxative used for constipation.
What are the adverse effects of PPI?
Hyponatraemia
Increased risk of C. difficile infections
Osteoporosis - increased risk of fractures
What are the indications of ranitidine?
2nd line to PPIs for peptic ulcer disease and gord.
What are the actions of H2 antagonists?
Reduces gastric acid secretion
What drugs can cause gynecomastia?
SOME DRUGS CREATE AWESOME KNOCKERS
Spironolactone (potassium sparing diuretic) Digitalis Cimetidine/ranitidine Alcohol Ketoconazole
What are the adverse effects of spironolactone? (2)
Gynecomastia, breast tenderness
Renal impairment/hyperkalaemia
What are the adverse effects of furosemide? (3)
Hypotension, hyponatraemia/hypokalaemia
What anti-emetic to use for pregnancy associated nausea?
- Antiemetics generally avoided where possible unless vomiting is becoming problematic e.g. dehydration.
- Short term use of an antihistamine is first choice e.g. cyclizine
What anti-emetic to use for chemotherapy induced?
5HT3 receptor antagonist e.g. ondansetron
What anti-emetic to use for opioid induced?
antihistamine is first choice e.g. cyclizine
What anti-emetic to use for motion sickness?
antihistamine is first choice e.g. cyclizine
What is action of antihistamine/ anti-emetic cyclizine?
Act by blocking H1 receptors within the VC
What is side effect of antihistamine cylizine/promethazine?
- Sedation: Particularly with promethazine
- Antimuscarinic properties: dry mouth and blurred vision.
What is the action of dopamine receptor antagonists and example?
All act at the CTZ chemoreceptor trigger zone to block dopamine receptors and promote gastric emptying and motility.
Metoclopramide
What are the CI of dopamine receptor antagonists?
Young children due to increased extrapyramidal side effects
GI perforation or obstruction can promote gastric emptying.
What is a side effect of dopamine receptor antagonists?
Extrapyramidal side effects such as muscle contractions, involuntary movements
-Diarrhoea.
Drugs that can cause dyspepsia?
aspirin + non-steroidal anti-inflammatory drugs (NSAIDs) can contribute to mucosal damage.
bisphosphonates e.g. risedronate.
