GI Drugs

Question 1

Name the H2 blockers

Answer 1

“-tidine”

cimetidine, ranitidine, famotidine, nizatidine

Question 2

Mechanism of H2 blockers

Answer 2

reversible block of the histamine H2 receptors –> decrease H+ secretion by parietal cells

Question 3

Use of H2 blockers

Answer 3

peptic ulcer, gastritis, mild GERD

Question 4

Toxicity of cimetidine specifically

Answer 4

inhibits cytochrome p450 (multiple drug interactions)
antiandrogenic effects (prolactin release, gynecomastia, impotence, decreased libido in males)
can cross BBB (cause confusion, dizziness, headaches) and can cross placenta

Question 5

Toxicity of cimetidine and ranitidine

Answer 5

decrease renal excretion of creatinine

Question 6

Name the proton pump inhibitors

Answer 6

“-prazole”

omeprazole, lansoprazole, esmeprazole, pantoprazole, dexlansoprazole

Question 7

Mech of PPIs

Answer 7

irreversibly inhibit H+/K+ ATPase in stomach parietal cells

Question 8

Use of PPIs

Answer 8

peptic ulcer, gastritis, esophageal reflux, Zollinger-Ellison syndrome

Question 9

Toxicity of PPIs

Answer 9

increased risk of C. difficile infection, pneumonia

decreased serum Mg2+ with long-term use

Question 10

Mechanism of bismuth and sucralfate

Answer 10

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

Question 11

Use of bismuth and sucralfate

Answer 11

increase ulcer healing, travelers diarrhea

Question 12

Mechanism of misoprostol

Answer 12

a PGE1 analog

increases production and secretion of gastric mucous barrier, decreases acid production

Question 13

Use of misoprostol

Answer 13

prevention of NSAID-induced peptic ulcers (NSAIDs block PGE1 production); maintenance of a PDA

also off label for induction of labor (ripens cervix)

Question 14

Toxicity of misoprostol

Answer 14

diarrhea

contraindicated in women of childbearing potential (abortifactant)

Question 15

Mechanism of octreotide

Answer 15

long-acting somatostatin analog; inhibits actions of many splanchnic vasodilatory hormones

Question 16

Use of octreotide

Answer 16

acute variceal bleeds, acromegaly, VIPoma, carcinoid tumor

Question 17

Toxicity of octreotide

Answer 17

nausea, cramps, steatorrhea

Question 18

Concern with use of antacids

Answer 18

can affect absorption, bioavailability, or urinary excretion of other drugs by altering gastric and urinary pH or by delaying gastric emptying

cause hypokalemia

Question 19

Toxicity of aluminum hydroxide

Answer 19

constipation and hypophosphatemia
proximal muscle weakness
osteodystrophy
seizures

Question 20

Toxicity of calcium carbonate

Answer 20

hypercalcemia

rebound acid

Question 21

Toxicity of magnesium hydroxide

Answer 21

diarrhea
hyporeflexia
hypotension
cardiac arrest

Question 22

Name the osmotic laxatives

Answer 22

Magnesium hydroxide, magnesium citrate, polyethylene glycol, lactulose

Question 23

Mechanism of osmotic laxatives

Answer 23

provide osmotic load to draw water into the GI lumen

Question 24

Use of osmotic laxatives

Answer 24

constipation

Question 25

Toxicity of osmotic laxatives

Answer 25

diarrhea, dehydration; may be abused by bulimics

Question 26

Specific use of lactulose

Answer 26

treats hepatic encephalopathy since gut flora degrade it into metabolites (lactic acid and acetic acid) that promote nitrogen excretion as NH4+

Question 27

Mechanism of sulfasalazine

Answer 27

combination of sulfapyridine (antibacterial) and 5-aminosalicylic acid (anti-inflammatory) activated by colonic bacteria

Question 28

Use of sulfasalazine

Answer 28

ulcerative colitis, Crohn disease (colitis component)

Question 29

Toxicity of sulfasalazine

Answer 29

malaise, nausea, sulfonamide toxicity, reversible oligospermia

Question 30

Mechanism of ondansetron

Answer 30

5-HT3 antagonist decreases vagal stimulation powerful central-acting antiemetic

Question 31

Use of ondansetron

Answer 31

control vomiting postoperatively and in pts receiving cancer chemotherapy

Question 32

Toxicity of ondansetron

Answer 32

headache, constipation, QT interval prolongation

Question 33

Mechanism of metoclopramide

Answer 33

D2 receptor antagonist increases resting tone, contractility, LES tone, motility does NOT influence colon transport time

Question 34

Use of metoclopramide

Answer 34

diabetic and postsurgery gastroparesis, antiemetic

Question 35

Toxicity of metoclopramide

Answer 35

increased parkinsonian effects, tardive dyskinesia | restlessness, drowsiness, fatigue, depression, diarrhea

Question 36

Drug interaction of metoclopramide

Answer 36

with digoxin and diabetic agents

Question 37

Contraindication of metoclopramide use

Answer 37

in patients with small bowel obstruction or Parkinson disease (due to D1 receptor blockade)

Question 38

Mechanism of orlistat

Answer 38

inhibits gastric and pancreatic lipase --> decreased breakdown and absorption of dietary fats

Question 39

Use of orlistat

Answer 39

weight loss

Question 40

Toxicity of orlistat

Answer 40

steatorrhea, decreased absorption of fat soluble vitamins