Gastrointestinal Drugs Flashcards
Famotidine
- H2-histamine antagonist that decreases cAMP and decreased H+
- results in decreased acid secretion and decreased pepsin due to increased pH
Indications for use of famotidine
- ulcers due to gastritis
- ulcers due to gastrinomas
Misoprostol
- prostaglandin EP3 receptor agonist that inhibits cAMP production and subsequently H+ production
- results in decreased acid secretion
Indications for use of misoprostol
- ulcer formation in dogs given NSAIDs
Omeprazole
- protein pump inhibitor that inhibits H/KATPase
- results in reduced acid secretion and sets the gastric pH at >3
Indications for use of omeprazole
- stress-related ulcers in horses
- any condition requiring acid suppression in dogs
(slow onset of action)
Sucralfate
- inactivates bile acids
- results in decreased hydrolysis of mucosal cell proteins
- increased prostanoid formation to increase mucosal cytoprotection
- increased EGF accumulation around ulcer
- increased gastric blood flow
Emetine
- locally-acting emetic agent
- alkaloid in syrup of ipecac that irritates the gastric mucosa to elicit vomiting
Apomorphine
- centrally-acting emetic agent
- D2-dopamine receptor agonist
- stimulates CNS vomiting center
Xylazine
- centrally-acting emetic agent
- stimulates alpha2-adrenergic receptors
- stimulates CNS vomiting center
Famotidine
- H2-histamine antagonist that leads to anti-emesis
- decreases acid output and lessens irritating effects of acid on stomach lining
Isopropamide and Glycopyrrolate
- mAChR antagonist that leads to anti-emesis
- decreases vagal afferent transmission to vomiting center
- decreases GI muscle spasms
- decreases GI secretions
Kaolin-pectin and Bismuth Subsalicylate (Pepto-bismol)
- coating agents that are anti-emetic and antidiarrheal
Metoclopramide
- blocks D2-dopamine receptors and stimulates gastric motility and prevents the relaxation of stomach that precedes vomiting
- also a dopamine antagonist in CNS to inhibit emesis
Diphenhydramine and Meclizine
- H1-histamine antagonist with anticholinergic activity
- reduces motion sickness by blocking CNS H1-histamine and muscarinic cholinergic receptors
Ondansetron
- blocks type 3 serotonin receptors on gastric vagal afferent fibers
- inhibits emesis in dogs associated with cancer chemotherapy or parvoviral infection
Maropitant
- block G protein-coupled type 1 neurokinin (substance P) receptors present in vomiting center
- inhibits emesis associated with cancer chemotherapy, motion sickness, parvoviral infections, gastroenteritis, and renal disease
Cisapride
- partial agonist at type 4 serotonin receptors, increasing ACh release from enteric neurons to stimulate motility
- stimulates motility throughout entire GI tract in dogs and cats
Erythromycin
- agonist at receptors in smooth muscle and gastroenteritic nerves for motilin
- stimulates motility of stomach and upper small intestine
- increases gastric emptying rate in dogs
Lidocaine
- blocks voltage-gated Na+ channels in enteric nerves
- stimulates intestinal motility
Mannitol and Sorbitol
- poorly absorbed in gut so draws water into intestinal tract and acts as a laxative
- increased fecal volume = increased intestinal motility
Bisacodyl
- stimulates enteric sensory nerves and functions as a laxative
- results in increased intestinal motility
- decreased absorption of H2O and ions
Pumpkin (yes the food)
- forms a mass of non-digestible matter in the intestines, thus decreasing H2O absorption
Mineral oil and Docusate Sodium
- coats fecal surface with a hydrophobic film or increases surface tension of lumina fluid
- leads to increased H2O content of feces
Loperamide and Codeine
- act through opioid receptors in intestinal wall and is antidiarrheal
- result in decreased intestinal propulsion and increased segmentation
- increases salt absorption and inhibits active anion secretion across intestinal epithelium
