GI Pharm Flashcards
H2 blocker examples
Cimetidine, ranitidine, famotidine, nizatidine
Mechanism of H2 blockers
Reverisble block of H2 receptors –> less H secretion by parietal cells
Clinical use of H2 blockers
Peptic ulcer, gastritis, mild esophageal reflux
Inhibitor of P450 H2 blocker
Cimetidine
Other effects of cimetidine
Antiadrogenic (prolactin release, gynecomastia, impotence, less libido in males); can cross BBB –> confusion, dizziness, headaches and placenta
H2 blockers that decrease renal excretion of creatinine
Ranitine, cimetidine
PPI examples
Omeprazole, lansoprazole, esomeprazole, pantoprazole, dexlansoprazole
Mechanism of PPIs
Irreversibly inhib H/K ATPase in stomach parietal cells
CLinical use of PPIs
Peptic ulcer, gastritis, esophageal reflux, ZE syndrome, part of therapy for H pylori, stress ulcer prophylaxis
Adverse effects of PPIs
Higher risk of C diff infxn, pneumonia, lower serum Mg w/ long term use
Consideration with antacids
Can affect bioavailability, absorption, urinary excretion of other drugs by altering gastric and urinary pH or by delaying gastric emptying
Can cause hypokalemia
Overuse of aluminum hydroxide
Constipation and hypophosphatemia, prox muscle weakness, osteodystrophy, seizures
Antacids
Aluminum hydroxide, Ca carbonate, mg hydroxide
Calcium carbonate overuse
Hypercalcemia (milk alkali syndrome), rebound acid increase
MG hydroxide overuse
Diarrhea, hyporeflexia, hypotension, caridac arrest
Bismuth and sulcralfate mechanism
Bind to ulcer base –> physical protection and allowing bicarb secretion to reestablish pH gradient in mucous laye r– requires acidic environment so not given w/ PPIs/H2 blockers
Clinical use of bismuth and sucralfate
Ulcer healing, travelers diarrhea
Misoprostol mechanism
PGE1 analog –> increased prodxn and secretino of gastric mucous barrier and less acid prodxn
Clinical use of misoprostol
Prevent NSAID peptic ulcers – off label to induce labor (ripens cervix)
Adverse effects of misoprostol
Diarrhea, CI in women of childbearing potential (abortifacent)
Octerotide mechanism
Long lasting somatostating analog – inhib secretion of various splanchnic vasodilatory hormones