GIT

Question 1

H2 blocker

Drug names

Answer 1

Cimetidine, Ranitidine, Famotidine, Nizatidine

Question 2

H2 blockers

MOA

Answer 2

Reversibly block H2-receptors – dec. H+ secretion by parietal cells.

Question 3

H2 blockers

Clinical use

Answer 3

Peptic ulcer
Gastritis
Mild esophageal reflux

Question 4

H2 blockers

Toxicity

Answer 4

> Cimetidine: CYP450 inhibitor, antiandrogenic, crosses BBB and placenta.
Cimetidine, ranitidine: dec. creatinine excretion.

Question 5

Proton Pump Inhibitors

Drug names

Answer 5

Omeprazole, Lansoprazole, Esomeprazole, Pantoprazole, Dexlanzoprazole

Question 6

Proton Pump Inhibitors

MOA

Answer 6

Irreversibly inhibit H/K ATPase in parietal cells.

Inc. gastric pH.

Question 7

Proton Pump Inhibitors

Clinical use

Answer 7

Peptic ulcer, gastritis, esophageal reflux

Zollinger-Ellison syndrome

Question 8

Proton Pump Inhibitors

Toxicity

Answer 8

C.difficile infection, pneumonia.

Dec. serum Mg w/ long-term use.

Question 9

Octreotide

MOA

Answer 9

Somatostatin analog.

Inhibits splanchnic vasoconstriction hormones.

Question 10

Octreotide

Clinical use

Answer 10

Acute variceal bleeds
Acromegaly
VIPoma, carcinoid tumors

Question 11

Misoprostol

MOA

Answer 11

PGE1 analog.
Inc. production/secretion of gastric mucosa.
Dec. acid production.

Question 12

Misoprostol

Clinical use

Answer 12

> Prevents NSAID-induced peptic ulcers.
Maintains PDA.
*CI in women of childbearing potential (abortifacient).

Question 13

Bismuth, Sucralfate

MOA, clinical use

Answer 13

> Bind to peptic ulcer base – protection – allows HCO3- secretion to reestablish pH gradient in mucous layer.
For ulcer healing, traveler’s diarrhea.

Question 14

Antacids

MOA, clinical use

Answer 14

Affect absorption, bioavailaibility, urinary excretion of other drugs – alters gastric acid and urinary pH, delays gastric emptying

Question 15

Antacids

Drug names

Answer 15

Aluminum hydroxide
Calcium carbonate
Magnesium hydroxide

Question 16

Osmotic laxatives

Drug names

Answer 16

Magnesium hydroxide
Magnesium citrate
Polyethylene glycol
Lactulose

Question 17

Osmotic laxatives

MOA

Answer 17

Provide osmotic load to draw H2O into GI lumen

Question 18

Osmotic laxatives (Lactulose)
Clinical use

Answer 18

Constipation.
Treat hepatic encephalopathy.
*Lactulose degraded into lactic acid and acetic acid by gut flora – promotes nitrogen excretion (NH4+).

Question 19

Metoclopramide

MOA

Answer 19

D2 receptor antagonist.
Inc. resting tone, contractility, LES tone, motility.
>No influence on colon transport time.

Question 20

Metoclopramide

Clinical use

Answer 20

Diabetic and postsurgery gastroparesis.

Antiemetic

Question 21

Metoclopramide

Toxicity

Answer 21

Inc. parkinsonian effects, tardive dyskinesia.

*CI in pts w/ small bowel obstruction, Parkinson dse (due to D1-receptor blockade).

Question 22

Ondansetron (5HT3 antagonist)

[MOA, use]

Answer 22

Normally, 5HT released from enterochromaffin cells in response to chemotherapy drugs – stimulates vagal afferents to initiate vomiting reflex.
Odansetron blocks the action of 5HT3 in vagal terminals at GIT and receptors in CTZ.
>For controlling post-op vomiting, and for pts undergoing chemotherapy.

Question 23

Sulfasalazine

[MOA, use]

Answer 23

> Combination of sulfapyridine (antibac) and 5-aminosalycylic acid (anti-inflam). >Activated by colonic bacteria.
For UC, CD (colitis component).