Lecture 16: GI Pharm

Question 1

Neural influences that lower LESp (4)

Answer 1

Cholinergic antagonists, alpha blockers, beta agonists, NO

Question 2

Drugs that lower LESp (4)

Answer 2

Theophylline, Ca2+-channel blockers, morphine/diazepam, serotonin

Question 3

Final common denominator for gastric acid secretion

Answer 3

H/K ATPase

Question 4

Prostaglandins cause what in the stomach (4)

Answer 4

Stimulate mucus production, epithelial cell repair, bicarbonate, mucosal blood flow

Question 5

Drugs for control of gastric acidity (4)

Answer 5

Antacids, cytoprotectants, H2 receptor antagonists, PPIs

Question 6

Antacids: mechanisms and types

Answer 6

Local neutralization of acid; aluminum and magnesium OH, calcium carbonate, sodium bicarbonate

Question 7

Cytoprotectants (3)

Answer 7

Sucralfate, misoprostol, bismuth compounds

Question 8

Bismuth: mechanism (3)

Answer 8

Binds to base of ulcer, promotes mucin and bicarbonate production, antibacterial effects

Question 9

Misoprostol: mechanism

Answer 9

Prostaglandin E analog, stimulates secretin of mucin/bicarb, increases mucosal blood flow; NOT AVAILABLE IN US

Question 10

Misoprostol: AEs

Answer 10

SM contraction –> cramps, diarrhea, contraindicated in pregnancy (chemical abortion)

Question 11

H2 Receptor antagonists: mechanism and examples

Answer 11

Competes with histamine for parietal cell receptors; cimetidine, ranitidine, famotidine, nizatidine

Question 12

H2 Receptor antagonists: use

Answer 12

Gastric/duodenal ulcers, uncomplicated GERD, stress ulcer prophylaxis

Question 13

H2 Receptor antagonists: drug interactions

Answer 13

Interferes w/ absorption of drugs that require an acidic environment; cimetidine is CYP-450 inhibitor, interfering with Phenytoin, theophylline, wararin

Question 14

Proton pump inhibitors: examples

Answer 14

-Prazoles

Question 15

Proton pump inhibitors: mechanism

Answer 15

Produg requires protonation in acidic environment AND enteric coating, absorbed in small intestine, IRREVERSIBLY binds to and inactivates H/K ATPase in parietal cell

Question 16

Proton pump inhibitors: uses

Answer 16

Gastric and duodenal ulcers, GERD, ZE syndrome, IV use for upper GI bleeding

Question 17

Proton pump inhibitors: AEs

Answer 17

Hypergastrinemia, potential increase in C difficile, potential increased risk of osteopenia

Question 18

Agents for increasing gastric motility

Answer 18

Cholinergics (bethanechol), metoclopramide (D2 antagonist and serotonin agonist), cisapride/tegaserod (serotonin agonists), domperiodone (block D2 receptors), erthromycin (binds to motilin receptor agonists)

Question 19

What serotonin receptor in the stomach is pro-motility?

Answer 19

5-HT4

Question 20

Problem with metoclopramide and advantage of domperidone

Answer 20

Also blocks D2 receptors in the brain, causing PD symptoms; domperidone does NOT cross the BB barrier