Flashcards in 1.1 GI Drugs Deck (20):
Which drugs are in the class antacids? (3)
1) Aluminum Hydroxide
2) Magnesium Hydroxide
3) Calcium Carbonate
What is the mechanism by which antacids work?
Weak bases that react with gastric HCL to form salt and water.
What is the final result of antacid use?
Increase stomach pH resulting in pepsin inactivation
Ca, Mg, Al molecules can?
Which generation H2 Blocker is Ranitidine?
(Cimeidine is only 1st generation)
What is the most important adverse effect of Magnesium Hydroxide?
What is the most important adverse effect of Aluminum hydroxide? (2)
What is the most important adverse effect of Calcium Carbonate? (3)
3) Constipation -> fecal compation
Aluminum Hydroxide may decrease bioavailability of? (3)
What is the difference between 1st and 2nd generation H2 blockers?
2nd gen do not inhibit CYP450 and are longer acting than Cimetidine
What are the adverse effects of Cimetidine?
Crosses the BBB and is prolactin stimulating. Has anti-androgenic properties which leads to gynecomastia
What are the adverse effects of 2nd generation H2 blockers? (3)
What are H2 blockers indicated for? (2)
1) Acute stress ulcer
2) Prevent aspiration pneumonia preoperatively
What is the mechanism by which H2 blockers act?
Block Gs mediated increase in cAMP that activates the H+/K+ pump -> 90% reduction of HCl secretion after single dose
Which GI drug class is activated after transport into parietal cell?
Why are PPI's used to treat hemorrhagic ulcers?
They support platelet aggregation and maintain clot integrity.
How does PPI's irreversibly inactivate parietal cells?
Form covalent bonds with cysteine resides on H+/K+ ATPase
What is the adverse effect with prolonged use of PPI and H2?
Decreases bioavailability of B12, digoxin and ketoconazole (acid required for absorption).
What are the adverse effects which have a higher risk with PPI toxicity? (4)
1) C. Difficile infection
3) Hip fractures
4) Decrease serum Magnesium with long term use