GI drugs Flashcards
Cimetidine, Ranitidine, famotidine, nizatidine
-Tidines
H2 blockers - reversible -> decreased H+ secretion from parietal cells
Use: Peptic ulcer, gastritis, mild GERD
Toxicity: Cimetidine - potent inhibitor of P450 , antiandrogenic effects (prolactin release, gyenecomastia, impotence, decreased libido males), cross BBB, placenta.
Both cimetidine and ranitidine decrease renal excretion of Cr.
Omeprazole, prazoles
Proton pump inhibitors
IRREVERSIBLE block of H/K ATPase in parietal cells
Use: Peptic ulcer, GERD, ZE syndrome, gastritis
Toxicity: increased risk of C. Difficile infection, pneumonia; long term: decreased serum Mg
Misoprostol
PGE1 analog, increase gastric mucosal barrer, decrease acid production
Use: prevent NSAID induced peptic ulcer (NSAIDs block PGE1 production), maintain PDA
induction of labor (off label)
CI in childbearing women ( abortificant)
Octreotide
Somatostatin analog; inhibit splanchnic vasodilatory hormone (D1?)
Use: acute variceal bleed, acromegaly, VIPoma, carcinoid tumor
Tox: N/V, steatorrhea
Antacid
Can cause hypokalemia
affect absoprtion, bioavailability or urinary excretion of other drugs by altering gastric pH or by delaying gastric emptying
Al Hydroxide, Ca Carbonate, Mg Hydroxide
Antacids
Al OH: constipation and hypophosphatemia; proximal muscle weakness, osteodystrophy, seizures
Ca Carbonate: Hypercalcemia, rebound acid increase
Mg OH: Diarrhea, hyporeflexia, hypotension, cardiac arrest
Mg Hydroxide, Mg citrate, polyethylene glycol, lactulose
Osmotic diuretics
Use: osmotic load to draw water into GI lumen
Use: constipation
Lactulose - treats hepatic encephalopathy (gut flora converts to lactic acid and acetic acid that promote nitrogen excretion as NH4+)
Sulfasalazine
Sulfapyridine (antibacterial) and 5-aminosalicyclic acid (anti-inflammatory). Activated by colonic bacteria
Use: UC, Crohn disease (colitis component)
Tox: sulfonamide toxicity, reversible oligospermia
Ondansetron
5-HT3 antagonist, decrease VAGAL stimulation. CENTRAL acting anti-emetic
Use: control post operative vomiting, chemo patients
Tox: QT interval prolongation, HA, constipation
Metoclopromide
D2 receptor antagonist. increases resting tone, contractility, LES tone, motility. Does not alter colon transit time
Use: Diabetic and posoperative gastroparesis; antiemetic
Tox: increase parkinsonian efffects, tardive dyskinesia. Diarrhea
Drug interaction: Digoxin and diabetic agents
CI: small bowel obstruction or Parkinson (due to D1 receptor blocker)
Orlistat
Inhibit gastric and pancreatic lipase -> decrease dietary fat absorption and breakdown
Use: weight loss
Toxicity: steatorrhea, decreased absorption of fat soluble vitamins
