GI Drugs Flashcards
What is the MoA of famotidine?
H2 receptor antagonist, reversible competitive inhibition. Reduces H ions and pepsin.
What is the MoA of omeprazole?
Irreversible proton pump (H-K ATPase) inhibitor. Prodrug
What is the MoA of sucralfate?
Disaccharide aluminum hydroxide - binds to damaged epithelial cells. Depends on acidic environment for activation. Also binds to multiple other drugs.
What is the MoA of bethanecol?
Cholinergic agonist at muscarinic receptors, increases amplitude of contraction but has minimal effect on coordination of small intestinal contractions.
What is the MoA of metoclopramide?
Para-aminobenzoic acid. Has central and peripheral anti-dopaminergic effect. Direct and indirect stimulator of cholinergic receptors. 5HT4 receptor agonist. Increases tone of LES, increases force and frequency of gastric antral contractions, relaxes pyloric sphincter, promotes peristalsis in upper GI (stomach, esophagus, pylorus). Also antiemetic (via central dopamine receptors)
What is the MoA of cisapride?
Indirect stimulation of cholinergic nerves mediated by serotonin (via 5HT5 receptors). Results in increased activity of the entire GI tract.
What is the MoA of domperidone?
Dopamine antagonist. Similar prokinetic properties to metoclopramide. Doesn’t cross blood brain barrier.
What is the MoA of erythromycin (as a prokinetic)?
Mimic effects of motilin. Increased LES pressures, uncoordinated stomach contractions, increased intestinal motility. Tolerance develops rapidly, likely d/t down regulation of motilin receptors.
What is the MoA of ranitidine?
H2 receptor antagonist, inhibits anticholinesterase activity. Prokinetic properties as well as antacid.
What is the MoA of maropitant?
Central antiemetic. NK1 receptor antagonist - blocks actions of substance P.
What is the MoA of antihistamines as anti-emetics?
Vestibular apparatus - effective for vomiting caused by motion sickness or inner ear disease. Can penetrate blood brain barrier at higher doses and have direct effect on vomiting center. Not effective as an anti-emetic for cats.
What is the MoA of ondansetron?
5HT3 receptor antagonist, centrally acting anti-emetic
