GI pharm

Question 1

Antacids: which are absorbable and adverse affects? non absorbable? characteristics?

Answer 1

Mg (diarrhea), Al (constipation), Ca (constipation) based.
NaHCO3 (alkalosis) based.
Rapid onset and short duration

Question 2

H-2RAs: suffix? mechanism? when should they be taken?

Answer 2

-tidine. competitive inhibition. Taken before bedtime (NO EATING afterwards b/c food signal can overcome blockade)

Question 3

H2RA drug interactions

Answer 3

cimetidine inhibits CYP450 (relevant for phenytoin, warfarin, theophylline b/c of narrow therapeutic window)

Question 4

PPIs: suffix? mechanism? side effects?

Answer 4

-prazole. Taken up by parietal cell, protonated, excreted, covalent bond with H/K ATPase (body must make new pump to regain secretion).
Slight risk of C. diff

Question 5

PPI: drug interactions

Answer 5

Omeprazole weakly interacts with phenytoin, warfarin, diazepam, CLOPIDOGREL

Question 6

What do you use PPIs for?

Answer 6

GERD, as part of H. pylori triple therapy (PPI, clarithromycin, amoxicillin), peptic ulcers (idiopathic, NSAID related), bleeding ulcer

Question 7

sucralfate: complications

Answer 7

problematic in pts with renal insufficiency due to Al. Works at acidic pH (don’t give with PPI, H2RA)

Question 8

Alosetron: what is it? what do you use it for? why was it withdrawn?

Answer 8

5-HT3 antagonist. Used to tx women with SEVERE IBS-D.

Ischemic colitis, constipation, death

Question 9

Drugs that cause constipation

Answer 9

verapamil, sucralfate, Ca or Al based antacids

Question 10

Linaclotide: who not to give it to

Answer 10

Children under 6.

Question 11

How to treat opioid constipation

Answer 11

peripheral mu antagonists: methylnaltrexone, alvimopan

Question 12

Sulfasalazine: mechanism of activation and action. Used to treat?

Answer 12

split by colonic bacteria into sulfapyridine (toxic) and 5-ASA which has local anti-inflamm effects for ulcerative colitis