GI drugs MOA, ADE, and interactions

Question 1

Antacids MOA

Answer 1

composed of a metal ion + base that work by neutralizing (buffering) hydrochloric acid (HCl) and forming a salt and water

Question 2

Histamine2-Receptor Antagonists (H2RA) MOA

Answer 2

reversibly compete with histamine at the H2 receptor sites in the parietal cell of the stomach to inhibit acid secretion

Question 3

Proton Pump Inhibitors (PPIs) MOA

Answer 3

irreversibly inhibit the K+-H+-ATPase (proton pump) which inhibits the final step in the secretion of hydrogen ions into the gastric lumen

Question 4

Synthetic Prostaglandin MOA

Answer 4

natural prostaglandins produced by gastric mucosa act to inhibit acid secretion and to protect deep mucosa against injury (cytoprotective); production of these prostaglandins blocked by NSAIDs

Question 5

Sucralfate (Carafate®)

Answer 5

Large aluminum salt (aluminum sucrose sulfate) forms a protective barrier at the ulcer site by binding to necrotic ulcer tissue; May also stimulate endogenous prostaglandin synthesis and adsorb bile salts

Question 6

Prokinetic Agents

Answer 6

Increase lower esophageal sphincter (LES) tone; Promote gastric emptying

Question 7

Metoclopramide (Reglan®)

Answer 7

Central dopamine [and serotonin (5-HT3) antagonist]; also increases response of GI tissue to acetylcholine resulting in enhanced motility and gastric emptying

Question 8

Erythromycin

Answer 8

Motilin agonist

Question 9

Domperidone

Answer 9

Dopamine antagonist that acts peripherally (limits extrapyramidal symptoms)

Question 10

Calcium ADE

Answer 10

Constipation

Question 11

Aluminum ADE

Answer 11

Constipation

Question 12

Magnesium ADE

Answer 12

Diarrhea

Question 13

Sodium ADE

Answer 13

Fluid retention

Question 14

Cimetidine ADE

Answer 14

Hematologic abnormalities, confusion, delusions, gynecomastia, increased etoh levels

Question 15

Ranitidine ADE

Answer 15

Hematologic abnormalities, confusion, delusions, increased etoh levels

Question 16

Nizatidine ADE

Answer 16

Hematologic abnormalities, confusion, delusions, increased etoh levels

Question 17

Famotidine ADE

Answer 17

Hematologic abnormalities, confusion, delusions

Question 18

Synthetic Prostaglandin ADE

Answer 18

GI effects common: diarrhea, abdominal cramping and nausea

Question 19

Sucralfate ADE

Answer 19

Al+ component can cause constipation and accumulates in patients with renal impairment

Question 20

Metoclopramide ADE

Answer 20

somnolence, increased prolactin, 2and extrapyramidal symptoms

Question 21

Erythromycin ADE

Answer 21

abdominal cramping, diarrhea

Question 22

Antacids + quinolone antibiotics, tetracycline, nitrofurantoin, isoniazid Drug interaction

Answer 22

Those drugs are bounded by antacids

Question 23

Which drugs require acidic environment?

Answer 23

iron supplements, ketoconazole, itraconazole capsule, sucralfate, calcium carbonate, levothyroxine

Question 24

Cimetidine Drug interaction

Answer 24

• Inhibits metabolism of other drugs via CYP450 (theophylline, phenytoin, warfarin)
• Drugs requiring acidic environment

Question 25

Ranitidine Drug interaction

Answer 25

• Inhibits metabolism of other drugs via CYP450 (theophylline, phenytoin, warfarin)
• Drugs requiring acidic environment

Question 26

Omeprazole Drug interaction

Answer 26

• Drugs requiring acidic environment
• Induces CYP1A4
• Inhibits CYP2C8, 2C9, 2C19, 3A3/4

Question 27

Sucralfate Drug interaction

Answer 27

Binds certain antibiotics (quinolone antibiotics, tetracycline, nitrofurantoin, isoniazid)