GI Drugs Flashcards
Omeprazole
Proton pump inhibitor
MOA: irreversibly inhibits H/K ATPase in stomach parietal cells
USES: peptic ulcer, gastritis, esophageal reflux, Zollinger-Ellison syndrome
TOXICITY: increased risk of C. Difficile infection, pneumonia. Hip fractures, decreased serum mg++ with long term use
Cimetidine
MOA: reversible inhibitor of histamine binding H2 receptor leading to decreased secretion of acid by parietal cells
USES: peptic ulcer, gastritis, mild esophageal reflux
TOXICITY: potent inhibitor of CYP450 which increases levels of drugs metabolized by CYPS; also has anti-androgenic effects (prolactin release, gynecomastia, impotence, decreased libido in males); can cross BBB (confusion, dizziness, headaches) and placenta. Both cimetidine and ranitidine decrease renal excretion of creatinine. Other H2 blockers are relatively free of these effects.
Misoprostol
MOA: PGE1 analog. increases production and secretion of gastric mucous barrier and decreases acid production
USES: prevention of NSAID-induced peptic ulcers (NSAIDs block PGE1 production); Maitenance of a PDA. Also used to induce labor (ripens cervix).
TOXICITY: diarrhea. Contraindicated in women of childbearing potential (abortificant)
Metoclopramide
MOA: D2 receptor antagonist. Increases resting tone, contractility, LES tone, motility. Does not influence colon transport time.
USES: diabetic and post-surgery gastroparesis; IV form as antiemetic
TOXICITY: Parkinsonian effects. Restlessness, drowsiness, fatigue, depression, nausea, diarrhea. Drug interaction with digoxin and diabetic agents. Contraindicated in patients with small bowel obstruction or Parkinsonian disease (D1-receptor blockade)
Sulfasalazine
MOA: a combination of sulfapyridine (antibacterial) and 5-aminosalicyclic acid (anti-inflammatory). Activated by colonic bacteria
USES: mild ulcerative colitis, Crohn’s disease
TOXICITY: Malaise, nausea, sulfonamide toxicity, reversible oligospermia
Ondansetron
MOA: 5-HT3 antagonist (antiemetic) decreases vagal stimulation; blocks binding of serotonin that initiates vomit reflex
USES: control vomiting postoperatively and in patients undergoing chemo
TOXICITY: headache, constipation
Scopolamine
Belladonna alkaloid
MOA: muscarinic receptor antagonist
PK: metered 3-day dose; percutaneous absorption, patch must be placed behind ear
USES: prevention of nausea and vomiting associated with motion sickness and recovery from anesthesia and surgery
TOXICITY: dry mouth, drowsiness
Ranitidine
MOA: reversible inhibitor of histamine binding H2 receptor leading to decreased secretion of acid by parietal cells
USES: peptic ulcer, gastritis, mild esophageal reflux
TOXICITY: Both cimetidine and ranitidine decrease renal excretion of creatinine. Other H2 blockers are relatively free of these effects.
Famotidine
MOA: reversible inhibitor of histamine binding H2 receptor leading to decreased secretion of acid by parietal cells
USES: peptic ulcer, gastritis, mild esophageal reflux
Nizatidine
MOA: reversible inhibitor of histamine binding H2 receptor leading to decreased secretion of acid by parietal cells
USES: peptic ulcer, gastritis, mild esophageal reflux
Lansoprazole
Proton pump inhibitor
MOA: irreversibly inhibits H/K ATPase in stomach parietal cells
USES: peptic ulcer, gastritis, esophageal reflux, Zollinger-Ellison syndrome
TOXICITY: increased risk of C. Difficile infection, pneumonia. Hip fractures, decreased serum mg++ with long term use
Esomeprazole
Proton pump inhibitor
MOA: irreversibly inhibits H/K ATPase in stomach parietal cells
USES: peptic ulcer, gastritis, esophageal reflux, Zollinger-Ellison syndrome
TOXICITY: increased risk of C. Difficile infection, pneumonia. Hip fractures, decreased serum mg++ with long term use
Pantoprazole
Proton pump inhibitor
MOA: irreversibly inhibits H/K ATPase in stomach parietal cells
USES: peptic ulcer, gastritis, esophageal reflux, Zollinger-Ellison syndrome
TOXICITY: increased risk of C. Difficile infection, pneumonia. Hip fractures, decreased serum mg++ with long term use
Dexlansoprazole
Proton pump inhibitor
MOA: irreversibly inhibits H/K ATPase in stomach parietal cells
USES: peptic ulcer, gastritis, esophageal reflux, Zollinger-Ellison syndrome
TOXICITY: increased risk of C. Difficile infection, pneumonia. Hip fractures, decreased serum mg++ with long term use
Bismuth
MOA a: bind to ulcer base, providing physical protection and allowing bicarbonate secretion to reestablish pH Gradient in the mucous layer
USES: increase ulcer healing, travelers diarrhea
Sucralfate
MOA a: bind to ulcer base, providing physical protection and allowing bicarbonate secretion to reestablish pH Gradient in the mucous layer
USES: increase ulcer healing, travelers diarrhea
Octreotide
MOA: long-acting somatostatin analog
USES: acute variceal bleeds, acromegaly, VIPoma, and carcinoid tumors
TOXICITY: nausea, cramps, steatorrhea
Aluminum hydroxide
Antacid
Can affect absorption, bioavailability, or urinary excretion of other drugs by altering gastric and urinary pH or bye laying gastric emptying. Can also cause hypokalemia. Overuse can cause constipation and hypophosphatemia; proximal muscle weakness, osteodystrophy, seizures
Calcium carbonate
Antacid
Can affect absorption, bioavailability, or urinary excretion of other drugs by altering gastric and urinary pH or bye laying gastric emptying. Can also cause hypokalemia. Overuse can cause hypercalcemia, rebound increased acid. Can chelate and decrease effectiveness of tetracyclines
Magnesium hydroxide
Antacid
Can affect absorption, bioavailability, or urinary excretion of other drugs by altering gastric and urinary pH or bye laying gastric emptying. Can also cause hypokalemia. Overuse can cause diarrhea, hyporeflexia, hypotension, cardiac arrest
Osmotic laxatives
Magnesium hydroxide, magnesium citrate, polyethylene glycol, lactulose
MOA: provides osmotic load to draw water out. Lactulose also treats hepatic encephalopathy since gut flora degrade it into metabolites (lactic acid and acetic acid) that promote nitrogen excretion as NH4+
USES: constipation
TOXICITY: diarrhea, dehydration; may be abused by bulimics
Orlistat
MOA: inhibits gastric and pancreatic lipase leading to decreased breakdown and absorption of dietary fats
USES: weight loss
TOXICITY: steatorrhea, decreased absorption of fat soluble vitamins
