1.1 GI Drugs

Question 1

Which drugs are in the class antacids? (3)

Answer 1

1) Aluminum Hydroxide
2) Magnesium Hydroxide
3) Calcium Carbonate

Question 2

What is the mechanism by which antacids work?

Answer 2

Weak bases that react with gastric HCL to form salt and water.

Question 3

What is the final result of antacid use?

Answer 3

Increase stomach pH resulting in pepsin inactivation

Question 4

Ca, Mg, Al molecules can?

Answer 4

Chelate tetracycline

Question 5

Which generation H2 Blocker is Ranitidine?

Answer 5

2nd Generation

Cimeidine is only 1st generation

Question 6

What is the most important adverse effect of Magnesium Hydroxide?

Answer 6

Diarrhea

Question 7

What is the most important adverse effect of Aluminum hydroxide? (2)

Answer 7

1) Constipation

2) Hypophosphatemia

Question 8

What is the most important adverse effect of Calcium Carbonate? (3)

Answer 8

1) Hypercalcemia
2) Nephrolithiasis
3) Constipation -> fecal compation

Question 9

Aluminum Hydroxide may decrease bioavailability of? (3)

Answer 9

1) Tetracyclines,
2) Digoxin
3) Antimuscarinics

Question 10

What is the difference between 1st and 2nd generation H2 blockers?

Answer 10

2nd gen do not inhibit CYP450 and are longer acting than Cimetidine

Question 11

What are the adverse effects of Cimetidine?

Answer 11

Crosses the BBB and is prolactin stimulating. Has anti-androgenic properties which leads to gynecomastia

Question 12

What are the adverse effects of 2nd generation H2 blockers? (3)

Answer 12

1) Nausea
2) Headache
3) Dizziness

Question 13

What are H2 blockers indicated for? (2)

Answer 13

1) Acute stress ulcer

2) Prevent aspiration pneumonia preoperatively

Question 14

What is the mechanism by which H2 blockers act?

Answer 14

Block Gs mediated increase in cAMP that activates the H+/K+ pump -> 90% reduction of HCl secretion after single dose

Question 15

Which GI drug class is activated after transport into parietal cell?

Answer 15

PPI’s

Question 16

Why are PPI’s used to treat hemorrhagic ulcers?

Answer 16

They support platelet aggregation and maintain clot integrity.

Question 17

How does PPI’s irreversibly inactivate parietal cells?

Answer 17

Form covalent bonds with cysteine resides on H+/K+ ATPase

Question 18

What is the adverse effect with prolonged use of PPI and H2?

Answer 18

Decreases bioavailability of B12, digoxin and ketoconazole (acid required for absorption).

Question 19

What are the adverse effects which have a higher risk with PPI toxicity? (4)

Answer 19

1) C. Difficile infection
2) Pneumonia
3) Hip fractures
4) Decrease serum Magnesium with long term use

Question 20

What are PPI’s indicated for?

Answer 20

1) GERD
2) Gastric Ulcers
3) MEN I
4) ZE syndrome
5) H. Pylori (with ABx)
6) NSAID induced ulcers