Acid Peptic Disorders Flashcards Preview

Pharmacology II > Acid Peptic Disorders > Flashcards

Flashcards in Acid Peptic Disorders Deck (31):
1

H. pylori ulcers

-Location: Duodenum > stomach
-Epigastric pain
-Superficial ulcer
-Less severe GI bleeding

2

NSAID ulcers

-Location: Stomach>duodenum
-asymptomatic
-Deep ulcer
-More severe GI bleeding

3

Stress ulcer

-ACUTE!
-Location: Stomach>duodenum
-Asymptomatic
-Superficial ulcer
-More severe GI bleeding

4

Parietal cells contain receptors for what 3 things?

1. Gastrin (CCK-B)
-from G cells
2. Histamine (H2)
3. Acetylcholine (muscarinic, M3)

5

How do antacids work

weak bases that react with stomach acid to form a salt and water

6

How long do antacids typically work?

If taken 1 hour after a meal, they effectively neutralize gastric acid for up to 2 hours

7

Antacids: Sodium Bicarbonate

Ex. baking soda, alka Seltzer
-React with gastric acid to form carbon dioxide and sodium chloride

ADE: 1. gastric distension 2. belching**

-be careful if kidneys don't work, could cause metabolic alkalosis
-becareful with NaCl absorption and fluid retention

8

Antacids: Calcium carbonate

Ex. Tums, Os-cal

-Reacts more slowly to form CO2 and CaCl2 (calcium chloride)

ADE: 1. belching 2. metabolic alkalosis 3. milk-alkali syndrome -->hypercalcemia if taken with dairy

9

Antacids: Magnesium hydroxide and aluminum hydroxide

Maalox (contains both magnesium and aluminum)

MOA:: reacts slowly to form magnesium chloride
-No gas or belching :)
-metabolic alkalosis uncommon

ADE: unabsorbed magnesium salts may cause diarrhea. Aluminum salts may cause constipation

10

Because antacids interact and effect the absorption of some medications, which should not be given within 2 hours of antacids?

1. Tetracyclines
2. Fluroquinolones
3. Itraconazole
4. Iron

11

H2 Receptor Antagonists

Ex. Cimetidine, Ranitidine, Famotidine, Nizatidine

-1st pass hepatic metabolism** (except Nizatidine)
Metabolism: hepatic, glomerular filtration, renal tubular secretion

12

When should H2 receptor blockers be given?

Bedtime

13

Most potent and least potent H2 blockers?

Least potent: cimetidine

Most potent: Famotidine

14

How long do H2 blockers work for?

10 hours (prescription strength)

6 hours (OTC)

15

What is the biggest ADE of H2 blockers?

Possible risk of nosocomial PNA in critically ill patients

16

Cimetidine unique ADEs

-Cytochrom P450 metabolized
-inhibits dihydrotestosterone to androgen receptors
-increases serum prolactin levels (galactorrhea in women)
-gynecomastia/impotence in men

17

PPIs: pharmacokinetics

Bioavailability is decreased by about 50% by food

-Irreversible inactivation of proton pump (H+/K+ ATPase which only exists in stomach)
-Rapid first-pass systemic hepatic

*Take 30-60 minutes before eating*
-Take at breakfast*

18

PPI: ADEs

-Diarrhea*
-Potentially effects absorption of iron, calcium, magnesium (increased fracture risk)
-increased risk of C. diff infection
-Rebound acid hypersecretion

19

PPIs: Drug interactions

-Omeprazole may inhibit metabolism of Warfarin
-Pantoprazole = no significant drug interactions
-Clopidogrel is a prodrug and can have reduced activation if used with some PPIs

20

What chemical is important in stimulating mucus and bicarbonate secretion and mucosal blood flow?

prostaglandins

21

Mucosal Protective Agents: Sucralfate

-forms physical barrier that restricts caustic damage
-Stimulates mucosal prostaglandin and bicarbonate secretion

22

Sucralfate: ADE

Constipation* (due to aluminum salt)
-Can bind to other medications and impair absorption

23

Gastrointestinal mucosa synthesize which prostaglandins?

PGE
PGF

24

Misoprostol

-PGE1
-Short half-life, so take it 3-4 times a day

MOA: inhibit acid, protect mucosa

other: stimulate intestinal electrolyte and fluid secretion, intestinal motility, uterine contractions

25

Misoprostol: ADE

-Diarrhea
-Cramping abdominal pain
-DO NOT USE in pregnancy or in women with child bearing potential (unless negative hCG), and on contraception)

26

Bismuth Compounds: types

1. Bismuth subsalicylate (ex. Pepto-Bismol)
-OTC

2. Bismuth subcitrate potassium
-Rx
-Contains metronidazole and tetracycline for treating H. pylori

27

Bismuth Compounds: metabolism

-99% of bismuth ends up in stool
-Salicylate dissociates with bismuth in the stomach and is readily absorbed and excreted in the urine.

28

Bismuth compounds: pharmacodynamics

Bismuth: creates a protective layer against pepsin and acid
-Bismuth has direct antimicrobial effects --->binds enterotoxins (antimicrobial activity against H. pylori)

Bismuth subsalicylate: reduces stool frequency and liquidity (inhibits intestinal prostaglandins and chloride secretion)

29

Bismuth Compounds: ADE

-blackening of stool
-darkening of tongue
-AVOID in renal insufficiency --> bismuth toxicity with encephalopathy, ataxia, headaches, confusion

-Remember that salicylate toxicity can cause tinnitus!

30

H. Pylori: Triple therapy Tx

PPI + Clarithromycin + Amoxicillin/Metronidazole

for 14 days

31

H. Pylori: Bismuth quadruple therapy

PPI + Bismuth + metronidazole + tetracycline