Pharm-GI Flashcards
What is the mechanism of action of cimetidine (1), ranitidine (2), famotidine, and nizatidine? Class of drug? Clinical use? Toxicity 1? 1 and 2? Others?
H2 blockers (4/suffix)
Reversible block of histamine H2 receptors leading to decr. H+ secretion by parietal cells
Peptic ulcer, gastritis, mild GERD
1=potent inhib. of P450, antiandrogenic effects, can cross BBB and placenta
1/2=decr. renal excretin of creatinine
3/4=free of s/x
Class of drug of omeprazole, lansoprazole, esomeprazole, pantoprazole, and dexlansoprazole? Mechanism? Clinical use? Toxicity?
PPIs (5 or suffix)
Irreversibly inhibit H+/K+ ATPase in stomach parietal cells
peptic ulcer, gastritis, esophageal reflux, and ZE syndrome
Incr. risk of C. diff, pneumonia
Decr. serum Mg2+ w/ long term use
What is the mechanism of bismuth, sucralfate? Clinical use?
Mechanism: bind to ulcer base, providing physical protection and allowing HCO3 secretion to reestablish pH gradient in mucosal layer.
Incr. ulcer healing
Traveler’s diarrhea
What is the mechanism of misoprostol? Clinical use? Off label? Toxicity? Contraindication?
PGE1 analog
incr. production and secretion of gastric mucosa barrier
Decr. acid production
PRevention of NSAID induced peptic ulcers
maintenance of PDA
Off label for induction of labor (ripens cervix)
Diarrhea.
CI=women of childbearing potential (abortifacient)
What is the mech of octreotide? Clinical use? Toxicity?
Long acting somatostatin analong
Inhibits action of many splanchnic vasoconstriction hormones
Acute variceal bleeds
acromegaly
VIPoma
Carcinoid tumors
Nausea, cramps, steatorrhea
What is the class of drug of Aluminum hydroxide (1), calcium carbonate (2), and magnesium hydroxide (3)? What is their toxicity? Toxicity of 1 when overused? 2? 3? Mechanism of action?
Antacids (3)
Can affect absorption, bioavailability, or urinary excretion of other drugs by altering gastric acid or urinary pH or by delaying gastric emptying
All can cause hypokalemia
1=constipation
2=hypercalcemia, rebound acid incr.
3=diarrhea
Aluminimum amount of feces
Mg=Must go to the bathroom
What is the class of drug of magnesium hydroxide magnesium citrate, polyethylene glycol, and lactulose (1)? Mechanism? Clinical use? Clinical use of 1? Toxicity?
Osmotic laxatives
Provide osmotic load to draw water into GI lumen
Constipation
1=hepatic encephalopathy (trapping urea as NH4+)
Diarrhea, dehydration; abuse by bulimics
What is the mechanism of sulfasalazine? How is it activated? Clinical use? Toxicity?
Sulfapyridine (antibacterial) and 5 aminosalicylic acid (anti-inflammatory)
Activated by colonic bacteria
UC, Crohns disease (colitis component)
Malaise, nausea, sulfonamide toxicity, reversible oligospermia
What is the mechanism of ondansetron? Clinical use? Toxicity?
5-HT3 antagonist;
Decr. vagal stimulation
Powerful central acting antiemetic
Control vomiting postoperatively
Cancer chemo anti-emetic
Headache, constipation, QT prolongation
What is the mechanism of Metoclopramide? Clinical use? Toxicity? CIs?
D2 receptor antagonist
Incr. resting tone, contractility, LES tone, motility.
Does not influence colon transport time
Diabetic and postsurgery gastroparesis,
antiemetic
Incr. parkinsonian effects, tardive dyskinesia
REstlessness, drowsiness, fatigue, depression
diarrhea
drug interaction w/ digoxin and diabetic agents
CI: Small bowel obstruction or parkinson disease
Mechanism of Orlistat? Clinical use? Toxicity?
Inhibits gastric and pancreatic lipase leading to decr. breakdown and absorption of dietary fats
Weight loss
Steatorrhea, decr. absorption of fat soluble vitamins
