Flashcards in GI Drugs Deck (46):
Cimetidine, Ranitidine, Famotidine, Nizatidine
*Take before you DINE, Table for 2"
Mechanism of H2 blockers
reversibly block histamine (H2) receptors on parietal cell
decreases H+ secretion by parietal cells
Clinical use of H2 blockers
toxicity of H2 blockers
Most H2 blockers are relatively free of S/E
Ranitidine-- decreases renal excretion of creatinine
potent inhibitor of p450 = multiple drug interactions
antiandrogenic effects (inc PRL release = gynecomastia, impotence & dec libido in males)
can cross BBB (confusion, dizzy, HA) & placenta
decreases renal excretion of creatinine
Proton Pump Inhibitors
Mechanism of PPI's
irreversibly inhibit H/K ATPase in stomach parietal cells
Clinical use of PPIs
toxicity of PPIs
inc risk of C. diff infxn & pneumonia
dec serum Mg with long-term use
Bismuth & Sucralfate MOA
bind to ulcer base = physical protection
allows HCO3 secretion to re-establish pH gradient in the mucus layer
clinical use of bismuth & sucralfate
PGE1 analog (prostaglandin)
increases production & secretion of gastric mucous barrier
decreases acid production
clinical use of Misoprostol
prevents NSAID-induced peptic ulcers
induces labor (ripens cervix)
Toxicity of Misoprostol
CONTRA if childbearing potential (abortifacient)
long-acting somatostatin analog (inhibits GF)
Clinical use of Octreotide
Acute variceal bleeds
(and tx acromegaly)
toxicity of Octreotide
nausea, cramps, steatorrhea
MOA & S/E of all antacids
affects absorption, bioavailability or urinary excretion of other drugs by altering gastric & urinary pH, or by delaying gastric emptying.
Aluminum hydroxide S/E
constipation (MINIMUM feces)
proximal muscle weakness
Magnesium hydroxide S/E
Diarrhea (Must Go)
Calcium carbonate S/E
rebound acid increase
decreases other drug effectiveness (chelates)-- esp tetracycline
MOA of osmotic laxatives
provide osmotic load = draws water out into lumen
lactulose also treats hepatic encephalopathy-- since gut flora degrade it into metabolites of lactic acid & acetic acids (promote nitrogen excretion as NH4+)
clinical use of osmotic laxatives
toxicity of osmotic laxatives
*abused by bulimics
monoclonal antibody to TNF-alpha
(-mab = monoclonal Ab)
use of Infliximab
Toxicity of Infliximab
infection (reactivation of latent TB)
combo of sulfapyridine (antibacterial) & 5-aminosalicylic acid (anti-inflammatory)
activated by colonic bacteria
Use of Sulfasalazine
Toxicity of Sulfasalazine
powerful centrally-active antiemetic
Clinical Use of Ondansetron
control vomiting postop
S/E of Ondansetron
D2 receptor antagonist
increases resting tone, contractility, LES tone, motility.
does NOT influence colon transport time
Clinical use of Metaclopramide
Toxicity of Metaclopramide
Inc parkinsonian effects
restlessness, drowsiness, fatigue, depression, nausea, diarrhea
*drug interaction w/ digoxin & diabetic tx
*CONTRA in pts with small bowel obstruction & parkinson's disease
What is octreotide used for?
How does octreotide work in treating esophageal varices?
Decreases glucagon and VIP which vasodilate splanchnic vessels.
Causes vasoconstriction of splanchnic vessels thereby diverting blood flow to the systemic circulation.
Does not cause systemic circulation vasoconstriction
What is pentagastrin?
A gastrin analog used to screen for carcinoid syndrome and medullary carcinoma of the thyroid
What over the counter drug may reduce the risk of adenomatous polyp formation in the colon?
aspirin - some colon adenomas have shown over expression of COX2
What is diphenoxylate?
An opiate anti-diarrheal structurally related to meperidine.
What is the MOA of diphenoxylate?
Binds mu receptors in the GI tract and causes slower motility.
What are the side effects of diphenoxylate?
Bloating and mild sedation
Can cause euphoria and physical dependence
What is diphenoxylate combined with to prevent abuse?
Atropine - causes dry mouth, blurry vision and nausea at higher doses.
Atropine + diphenoxylate = lomotil