Digestion & Metabolism I: Gastric Drugs Flashcards
sucralfate (sucramal)
type = chemical diffusion barrier
method of action?
- dissociates into sucralfate octasulfate in stomach acid
- coats stomach epithelium to form a paste and prevent ulcers from reaching nerves and causing pain
famotidine (pepcid)
type = 3rd generation H2 receptor antagonist
method of action?
blocks histamine-mediated gastric acid secretion (ACh from ENS –> ECL cell –> histamine released –> H2 receptor on parietal cell –> gastric acid
omeprazole (prilosec)
**something special about it
type = H, K, ATPase proton pump INHIBITOR
method of action?
- is an enteric-coated capsule/tablet that allows it to survive stomach
- get absorbed by duodenum, and then reach parietal cell to be protonated
- once protonated, can bind covalently to proton pump to inhibit its function and stop stomach acid production
**can last longer because irreversibly binds, so until proton pump is replaced (~48 hours), function is inhibited
pantoprazole (protonix)
type = H, K, ATPase proton pump INHIBITOR
method of action?
- just like omeprazole, is a weak base
- supplied as a delayed-release tablet to survive stomach
- absorbed by duodenum, goes to parietal cell to be protonated, and binds irreversibly to proton pump
cisapride (propulsid)
type = promotility drug
method of action?
- 5HT4 receptor AGONIST to directly stimulate gastric motility/contraction
- ALSO increases ACh secretion at ENS nerve endings to increase gastric emptying
metaclopromide (reglan)
**ALTERNATIVE USE
type = promotility drug
method of action?
- dopamine type 2 receptor ANTAGONIST/BLOCKER
- INCREASED LES/stomach muscle tone to prevent reflux
- also increases ACh release from ENS nerve endings to increase ACh-mediated gastric motility
**ALTERNATIVE USE
type = dopamine type 2 receptor antagonist, anti-emetic drug
method of action?
- blocks dopamine type 2 receptors in brain and prevents vomiting
erythromycin/azithromycin
type = promotility drug/antibiotics
method of action?
- WEAK agonists of MOTILIN GPCR which causes gastric motility
- weak because need a high concentration for effect to occur
- motilin binds to motilin GPCR on ENTERIC NEURONS and causes gastric motility
ranitidine (zantac)/nizitidine (axid)
type = promotility drugs
method of action?
- WEAK inhibitors of acetycholinesterase which increases ACh at synapses causing INCREASED GASTRIC MOTILITY
chloropromazine
type = alpha 2 adrenergic agonist (anti-emetic drug)
method of action
- binds to alpha 2 adrenergic receptors and causes vasodilation
- Overall, ANTI-VOMITING
ondansteron (Zofran)
type = 5HT3 serotonin antagonist, anti-emetic
method of action?
- blocks 5HT3 serotonin receptors from functioning in brain and GI tract
maropitant (Cerenia)
type = neurokinin-1 antagonists, anti-emetic
method of action?
- blocks NK-1 receptor activation in brain and emetic center to prevent vomiting
