G.I. Drugs Flashcards Preview

Pharmacology Test #5 > G.I. Drugs > Flashcards

Flashcards in G.I. Drugs Deck (88)
Loading flashcards...
1

Two major classes of drugs affecting the GI system

Drugs affecting secretion
Drugs affecting GI motility

2

Classes of drugs affecting secretion

Antacids
H2 histamine receptor antagonists
Proton pump inhibitors

3

Class of drugs affecting GI motility

Prokinetic
Anti-diarrheal/emetics

4

Drugs affecting GI secretions are used in the treatment of

1. Peptic ulcers (gastric or guodenal)
2. Gastroesophageal reflux (GERD/Barrett's Esophagus)
3. Hypersecretory states such as Zollinger-Ellison syndrome

5

Ulcers are a failure of

mucosal protection

6

What do proton pump inhibitors inhibit

H+/K+ ATPase in the parietal cells

7

Name the 4 antacids

1. NaHCO3
2. CaCO3
3. AL(OH)3
4. Mg(OH)2

8

Adverse effects of NaHCO3

systemic alkalosis, fluid retention

9

Adverse effects of CaCO3

Milk-alkali syndrome: hypercalcemia and nephrolithiasis

10

Adverse effects of Al(OH)3

Constipation and hypophosphatemia

11

Adverse effects of Mg(OH)2

Diarrhea and hypermagesemia

12

What is Alternagel?

Al(OH)3

13

What is Mallox and Mylanta?

Al(OH)3 and Mg(OH)2

14

What is Tums?

CaCO3

15

What is Gaviscon and what does it do?

Sodium alginate + antacids: viscous, weak base; prevents reflex and effective in GERD

16

What is Mylicon/Phazyme and what do they do?

Simethicone: mild surfactant; enhances the release of gas

17

First generation H2-histamine receptor antagonists

Diphenhydramine and Cimetidine

18

Mechanism of Cimetidine

competitive antagonist of H2 histamine receptor

19

Cimetidine reduces gastric acid secretion in response to what?

in response to histamine, gastrin, and acetylcholine

20

Cimetidine inhibits which metabolic enzymes? Which drugs does this effect?

Inhibits CYP 2C6 and 2D9: warfarin, phenytoin, theophylline, benzodiazepines and sulfonylureas

21

Side effects of Cimetidine?

1. CNS effects (confusion, delirium headaches) seen with IV admin to elderly patients
2. Antiandrogen (gynecomastia, impotence)
3. Inhibition of estradiol metabolism (galactorrhea)
4. Thrombocytopenia

22

Second generation H2 blockers

Ranitidine (Zantac); Nizatidine (Axid); Famotidine (Pepcid)

23

How are second generation H2 blockers different from 1st generation H2 blockers?

longer half life; increase ethanol bioavailability by reducing first-pass metabolism (except Famotidine); fewer effects of CYP450 system; greater potency

24

Proton pump inhibitors (PPIs)

Omeprezole; lansoprazole; raberprazole, pantoprazole

25

Action of proton pump inhibitors

Irreversible inhibitor of H+/K+ ATPase

26

What are PPIs activated by?

Prodrugs: activated by acidic pH

27

Describe the pharmacokinetics of PPIs

Short plasma half-life (~1hr) but long duration of action (>24 hrs)

28

PPIs can cause hypergastrinemia, which can result in?

can result in rebound hypersecretion of gastric acids

29

Increase in gastric pH with PPIs can affect what?

drug absorption and potentially increase risk of infections

30

Adverse effects of PPIs

few side effects; nausea most common; Vitamin B12 deficiency; osteoporotic fracture