GI Drugs

Question 1

H2 blockers

Answer 1

cimetidine, ranitidine, famotidine, nizatidine

Question 2

H2 blockers MOA, use, SE

Answer 2

MOA - reversible block of histamine H2 receptors -> decreased H+ secretion by parietal cells
Use - peptic ulcer, gastritis, mild esophageal reflux
SE - cimetidine - inhibitor of P450, antiandrogenic effects (prolactin release, gynecomastia), crosses BBB; all can cause thrombocytopenia

Question 3

PPI

Answer 3

omeprazole, lansoprazole, esomeprazole, pantoprazole, dexlansoprazole

Question 4

PPI MOA, use, SE

Answer 4

MOA - irreversibly inhibit H+/K+ ATPase in stomach parietal cells
use - peptic ulcer, gastritis, esophageal reflux, ZE syndrome, H. pylori treatment
SE - increased risk of C. difficile infection

Question 5

3 Types of antacids; what SE do they all share?

Answer 5

1. aluminum hydroxide
2. calcium carbonate
3. magnesium hydroxide

All can cause hypokalemia

Question 6

SE of aluminum hydroxide

Answer 6

constipation and hypophosphatemia; proximal muscle weakness, osteodystrophy, seizures

Question 7

SE of calcium carbonate

Answer 7

hypercalcemia, rebound acid increases; can chelate and decrease effectiveness of other drugs

Question 8

SE of magnesium hydroxide

Answer 8

diarrhea, hyporeflexia, hypotension, cardiac arrest (smooth muscle relaxation)

Question 9

MOA of bismuth, sucralfate

Answer 9

bind to ulcer base, provides physical protection

can be used for traveler’s diarrhea

Question 10

Misoprostol MOA, use, SE

Answer 10

MOA - PGE1 analog; increases production and secretion of gastric mucous barrier, decreases acid production
Use - prevention of NSAID-induced peptic ulcers, also used off-label for induction of labor
SE - diarrhea; C/I in women of childbearing potential

Question 11

Octreotide MOA, use, SE

Answer 11

MOA - long-acting somatostatin analog; inhibits secretion of vasodilatory hormones
Use - acute vatical bleeds, acromegaly, VIPoma, carcinoma tumors
SE - N, cramps, steatorrhea, increased risk of cholelithiasis due to CCK inhibition

Question 12

Ondansetron MOA, use, SE

Answer 12

MOA - 5-HT3 antagonist, decreases vagal stimulation; powerful central-acting emetic
Use - post-op vomiting, chemo vomiting, & pregnancy nausea

Question 13

Metoclopramide MOA, use, SE

Answer 13

MOA - D2 receptor antagonist, 5HT4 stimulator -> increases resting tone, contractility, LES tone, motility, promotes gastric emptying
Use - diabetic and post surgery gastroparesis, antiemetic, persistent GERD
SE - increase parkinsonian effects, tardive dyskinesia

Question 14

4 Types of laxatives

Answer 14

bulk-forming, osmotic, stimulants, emollients

Question 15

Bulk-forming laxatives (names, MOA, SE)

Answer 15

psyllium, methylcellulose
MOA - draw water into gut lumen
SE - bloating

Question 16

Osmotic laxatives (names, MOA, SE)

Answer 16

magnesium hydroxide, magnesium citrate, polyethylene glycol, lactulose
MOA - provide osmotic load to draw water into GI lumen
SE - diarrhea, dehydration

Question 17

Stimulant laxatives (names, MOA, SE)

Answer 17

Senna
MOA - enteric nerve stimulation -> colonic contraction
SE - diarrhea, melanosis coli

Question 18

Emollients laxatives (names, MOA, SE)

Answer 18

docusate
MOA - osmotic draw into lumen -> increase water absorption by stool
SE - diarrhea