E2: GI Drugz Flashcards
MOA for antacids
Inorganic bases that neutralize HCl to form salt and H2O
List the 2 drugs in the Antacids class
Magnesium Hydroxide
Aluminum Hydroxide
What is the primary adverse effect of Magnesium Hydroxide? Aluminum Hydroxide? How can this be improved?
Mg = diarrhea Al = constipation
Combine together to cancel out these effects
What are the uses of Antacids?
Symptomatic short term relief of heartburn and GERD (or used as adjunct therapy)
Antacids are contraindicated in what pt population?
Patients w/ kidney dysfunction (can cause accumulation of toxins)
Antacids have a high potential for _____.
Drug interactions
Name the 2 drugs in the H2 blockers class.
Cimetidine
Ranitidine (Zantac)
MOA for H2 blockers
COMPETITIVE antagonists of H2
When are H2 blockers most effective? When should you educate your patients to take them?
Most effective at decreasing nocturnal acid formation
Pts should take at bedtime!
What are 4 uses of H2 blockers?
- Duodenal and gastric ulcers*
- Given w/ H1 antagonists for severe allergic rxn (decrease vasodilation)*
- Adjuncts for GERD and ZES
- Given pre-operatively in case of aspiration
*Most important
H2 blockers are metabolized by the _____ and excreted by the _____.
Metabolized by liver
Excreted by kidney
What are 3 general adverse effects of H2 blockers? What is a specific adverse effect for Cimetidine and in what how can this be used therapeutically?
- HA
- Nausea
- Confusion (elderly)
Chronic cemetidine: Anti-androgenic effects (ex: gynecomastia) - used to tx HIRSUITISM in females
Which H2 blocker can cause drug interactions? What liver enzyme does this drug inhibit?
Cimetidine inhibits CYP3A4
*Drug interactions with phenytoin, warfarin, theophylline, benzos, TCAs, etc.
Name the 2 PPIs
Omeprazole
Esomeprazole
MOA for PPIs
IRREVERSIBLY inhibit the proton pump in the final stage of gastric acid production (binds to H/K pump)
What is the DOC for GERD w/ esophagitis?
PPIs - extremely effective!
In what form are PPIs ingested into the body?
Ingested as prodrugs –> must be converted to active sulfenamide
How long does it take for the PPIs (Omeprazole, Esomeprazole) to start working? How long do their effects last once discontinued?
2-5 days to start working
Effects last 24-48 hrs upon discontinuation
Though usually minimal, what are the adverse effects of PPIs? (6)
- Nausea/Diarrhea/Abd. colic
- Increased URIs (specifically pneumonia)
Chronic use:
- Decreased Ca absorption (risk for osteoporosis)
- Hypomagnesia
- Vit B12 deficiency
- Increased risk of CKD
What liver enzyme does Omeprazole inhibit? This effects the metabolism of what 3 other drugs?
Inhibits CYP249
Decreased metabolism of phenytoin, diazepam, and warfarin
What drug is a Cytoprotective Agent? What is the MOA?
Misoprostol
MOA: Prostaglandin E1 analogue (increased secretion of mucous, decreased acid secretion)