GI drugs

Question 1

H2 blockers (names, use tox)

Answer 1

cimetidine, ranitidine, famotidine, nizatidine

• peptic ulcers, gastritis, mild GERD
• cimetidine is a p450 inhibitor and has anti-androgen effects
• both cimetidine and rantidine have decreased renal excretion of creatinine
• others dont really have side effects

Question 2

PPIs

Answer 2

• prazoles
• inhibit H/K ATPase in stomach parietal cells irreversibly
• used in peptic ulcers, gastritis, esophageal reflux, Z-E syndrome
• increased risk of C. diff infection, pneumonia
• hip fractures and decreased serum Mg with long-term use

Question 3

bismuth, sucralfate

Answer 3

bind to ulcer base, providing physical protection and allowing HCO3- secretion to reestablish pH gradient in the mucous layer
- used to increase ulcer healing, and in travelers diarrhea

Question 4

misoprostol

Answer 4

PGE1 analog used to increase production and secretion of gastric mucous barrier and decrease acid production

• used in prevention of NSAID ulcers
• tox: diarrhea, abortifactant

Question 5

octreotide

Answer 5

• somatostatin analog
• used in acute variceal bleeds, acromegaly, VIPoma, and carcinoid tumors
• tox: nausea, cramps, steatorrhea

Question 6

aluminum hydroxide

Answer 6

• antacid that can cause hypokalemia, constipation, hypophosphatemia, proximal muscle weakness, osteodystrophy and seizures

Question 7

calcium carbonate

Answer 7

• antacid that can cause hypokalemia, hypercalcemia and rebound increase in acid

Question 8

magnesium hydroxide

Answer 8

• antacid that can cause hypokalemia, diarrhea, hyporeflexia, hypotension, cardiac arrest

Question 9

osmotic laxatives

Answer 9

• mg hydroxide, mg citrate, polyethylene glycol, lactulose
• provide osmotic load to draw water out (same mech as lactase def)
• used in constipation
• SE: diarrhea, dehydration, may be abused by bulimics

Question 10

sulfasTalazine

Answer 10

• a combination of sulfapyridine (antibacterial) and 5-aminosalicylic acid (anti-inflammatory)
• activated by colonic bacteria
• used in crohns and UC
• tox: malaise, nausea, sulfonamide tox, reversible oligospermia

Question 11

ondansetron

Answer 11

• 5HT3 antagonist, decreases vagal stimulation
• powerful central antiemetic
• control vomiting postop and in patients undergoing cancer chemotherapy
• tox: headache, constipation

Question 12

metoclopramide

Answer 12

• D2 receptor antagonist
• increased resting tone, contractility
• used in gastroparesis, antiemetic
• tox: increased parkinsonian effects, restlessness, drowsiness, fatigue, depression, nausea, diarrhea
• contraindicated with SBO or parkinsons