GI

Question 1

H2 blockers

• end in?
• mech, clin use, tox

Answer 1

“-dine” (Table for 2=dine), Cimetidine, Ranitidine, Famotidine, Nizatidine
- Reversibly block hist H2 Rs, decr H+ secretion by parietal cells
- peptic ulcer, gastritis, mild eso reflux
- Cimetidine inhib’s P450, is antiandrogenic, can X BBB and placenta
Cimetidine and ranitidine decr renal excretion of Cr

Question 2

PPIs

• end in?
• mech, clin use, tox

Answer 2

“prazole” Omeprazole, lansoprazole, esomeprazole, pantoprazole, dexlansoprazole

• irreversibly inhib H/K ATPase in stomach parietal cells
• PUD, gastritis, eso reflux, ZES
• incr’d risk C.dif infec, pneumo, hip fx bc decr’d serum Mg w/ LT use

Question 3

Bismuth

- mech, clin use

Answer 3

• binds ulcer base -> protects it and allows HCO3- secretion to reestablish pH grad in mucous layer
• incr ulcer healing, traveler’s D

Question 4

Sucralfate

- mech, clin use

Answer 4

• binds ulcer base -> protects it and allows HCO3- secretion to reestablish pH grad in mucous layer
• incr ulcer healing, traveler’s D

Question 5

Misoprostol

- mech, clin use, tox

Answer 5

• PGE1 analog, incr prod/secretion of gastric mucous barrier, decr acid prod
• prevent NSAID ulcers, maintain PDA, induce labor (ripens cervix)
• D, C/I’d in women of childbearing potential (abortifacient)

Question 6

Octrotide

- mech, clin use, tox

Answer 6

• long-acting somatostatin analog
• acute variceal bleeds, acromegaly, VIPoma, carcinoid tumors
• N, cramps, steatorrhea

Question 7

Antacid use can cause?
Overuse of the following, cause?
- Aluminum hydroxide
- Mg hydroxide
- Ca carbonate

Answer 7

HypoK

• constipation, hypoPhos, prox m. wkns, osteodystrophy, seizures
• D, hyporeflexia, hypotension, cardiac arrest
• hyperCa, rebound incr’d acid (and can chelate other drugs, like tetracycline)

Question 8

Osmotic laxatives = (4)

- mech, clin use, tox

Answer 8

Mg hydroxide, Mg citrate, polyethylene glycol, lactulose

• provide osmotic load to draw water out
• Constipation
• D, dehydration, abused by bulimics

Question 9

Lactulose is used as osmotic laxative and as what?

Answer 9

Treat hep encephalopathy bc gut flora degrades it into metabolites (lactic acid + acetic acid) that promote N excretion as NH4+

Question 10

Infliximab

- mech, clin use, tox

Answer 10

• mAb to TNFa
• CD, UC, RA
• infec (react’n of latent TB), F, hypotension

Question 11

Sulfasalazine

- mech, clin use, tox

Answer 11

• combo of sulfapyridine (antibac) and 5-ASA (anti-inflamm), act’d by colonic bac
• UC, CD
• malaise, N, sulfonamide tox, reversible oligospermia

Question 12

Ondansetron

- mech, clin use, tox

Answer 12

• 5-HT3 antag, powerful central-acting antiemetic
• control V postop and in chemo pt’s
• HA, constipation

Question 13

Metoclopramide

• mech, clin use, tox
• C/I’d in?

Answer 13

• D2 R antag, incr’d resting tone, contrac, LES tone, motil (doesn’t influence colonic transport time)
• DM and postop gastroparesis, antiemetic
• incr’d parkinsonian effects (restlessness, drowsiness, fatigue, depression, N, D); drug interaction w/ digoxin and DM agents
• pt’s w/ smI obstruc or Parkinson’s dz