Gastric Pharm

Question 1

sucralfate

Answer 1

chemical diffusion barrier drug
- sucrose octasulfate polymerizes forming a paste that binds to damaged gastric epithelium
- forms a physical barrier against stomach acid

Question 2

H2 receptor function

Answer 2

H2 receptor is located on parietal cells and regulates histamine-mediated gastric acid secretion

Question 3

famotidine

Answer 3

3rd generation H2 selective antagonist from Merck

Question 4

omeprazole

Answer 4

proton-pump inhibitor
supplied as an enteric-coated capsule to survive the stomach
- once in the low pH environment around the parietal cell, it becomes protonated
- protonated form of the drug binds covalently and irreversibly to and inactivates the proton pump

Question 5

omeprazole efficacy

Answer 5

it has a short half life by its efficacy lasts longer than predicted from plasma drug concentration (activity is still present despite not having a plasma concentration)

Question 6

pantoprazole

Answer 6

proton pump inhibitor
- weak base, like omeprazole
- supplied as a delayed-release tablet and delayed-release granules to survive the stomach
- same mechanism as omeprazole

Question 7

promotility drugs

Answer 7

help control acid reflux by strengthening the lower esophageal sphincter, decreases stomach emptying time allowing less time for reflux to occur, stimulates smooth muscle contraction of stomach to speed emptying allowing less time for reflux to occur

Question 8

cisapride

Answer 8

promotility drug
- 5HT4 serotonin receptor agonist that directly stimulates gastric motility
- increases the release of Ach nerve endings in the myenteric plexus controlling gut motility in the ENS

Question 9

metoclopramide

Answer 9

promotility drug
- D2 antagonist (dopamine type 2 antagonist)
- results in increased LES and stomach tone
- results in increased nerve terminal Ach release and therefore increased Ach-mediated gastric motility

Question 10

erythromycin and azithromycin

Answer 10

promotility drug
- antibiotics that are weak agonists for the Motilin receptor
- motilin binding to the motilin receptor on enteric neurons stimulates gastric motility

Question 11

ranitidine and nizatidine

Answer 11

promotility drugs
weak inhibitors of acetylcholinesterase
blocking acetylcholinesterase results in increased Ach synapse increasing gastric motility

Question 12

chlorpromazine

Answer 12

antiemetic, alpha 2 adrenergic antagonist

Question 13

metoclopramide

Answer 13

antiemetic that blocks D2 receptors in the brain

Question 14

ondansteron

Answer 14

antiemetic drug, blocking 5HT3 serotonin receptors in the brain and gut

Question 15

Maropitant (cerenia)

Answer 15

antiemetic, blocks NK-1 receptor activation in brain to reduce vomiting