Pharm: Acid Peptic Drugs

Question 0

What intracellular milieu within parietal cells triggers acid secretion? What protein secretes the acid?

Answer 0

(1) increased cAMP and Ca++

(2) H+/K+ ATPase pump

Question 1

What are the notable receptors on parietal cells?

Answer 1

(1) H2 receptor
(2) M3 receptor
(3) gastrin/CCK-B receptor

Question 2

How is the activity of pepsin regulated by pH?

Answer 2

It is inactivated above a pH of 4.0 and irreversibly so above a pH of 6.0.

Question 3

What is the primary cause if bile gastritis?

Answer 3

Surgery in which the integrity of the pylorus has been disrupted.

Question 4

How does caffeine contribute to ulcer formation?

Answer 4

It enhances acid secretion and lowers LES pressure.

Question 5

How does alcohol contribute to ulcer formation?

Answer 5

It is directly toxic to upper GI organs.

Question 6

How does tobacco contribute to ulcer formation?

Answer 6

It impairs mucosal protective factors and may increase acid secretion.

Question 7

From where is bicarbonate and mucus secreted?

Answer 7

(1) stomach
(2) duodenal surface epithelial cells
(3) mucus neck cells
(4) Brunner glands

Question 8

How do PGE1 and PGE2 protect against PUD?

Answer 8

(1) increase bicarbonate secretion
(2) increase mucus thickness
(3) increase mucosal blood flow

Question 9

What are the notable H2 antagonists?

Answer 9

(1) cimetidine (Tagamet)
(2) ranitidine (Zantac)
(3) nizatidine (Axid)
(4) famotidine (Pepcid)

Question 10

What are the pharmacokinetics of H2 receptor antagonists?

Answer 10

Rapidly absorbed with quick onset.
Hepatic metabolism via P450 system.
Renal excretion.
Continuous dosing keeps gastric pH > 4.0.

Question 11

How do different types of H2 receptor antagonists interact with the P450 system?

Answer 11

(1) cimetidine binds avidly.
(2) ranitidine, less so.
(3) famotidine and nizatidine, not at all.

Question 12

What are the notable PPIs?

Answer 12

(1) omeprazole (Prilosec)
(2) lansoprazole (Prevacid)
(3) rabeprazole (Aciphex)
(4) pantoprazole (Protonix)
(5) esomeprazole (Nexium)

Question 13

What is the MoA of PPIs?

Answer 13

They irreversibly block the H+/K+ ATPase pump.

Question 14

Describe the processing of PPIs from ingestion to activity within the stomach.

Answer 14

(1) Taken orally as prodrugs in an acid-resistant coating.
(2) The coating is dissolved in the alkaline environment of the small intestine.
(3) The lipophilic prodrug is delivered throughout the bloodstream, remaining inactive at neutral pH or higher.
(4) It arrives at parietal cells protonated, concentrated and sulfonated.

Question 15

What are the adverse effects of PPIs?

Answer 15

(1) increased gastrin secretion
(2) hip fracture from long-term use
(3) possibly increased respiratory infections

Question 16

What is the MoA of antacids?

Answer 16

As weak bases they neutralize gastric acid to form a salt and water.

Question 17

What are the different chemical compositions of antacids?

Answer 17

(1) aluminum and magnesium hydroxides (Mylanta and Maalox)
(2) sodium bicarbonate (Alka Seltzer)
(3) calcium carbonate (Tums)

Question 18

What are adverse effects of antacids?

Answer 18

(1) chalky taste
(2) Mg++: diarrhea, muscle weakness
(3) Al+++: constipation, may contribute to osteomalacia
(4) Ca++: rebound acid secretion, nephrocalcinosis

Question 19

What treatment regimens are commonly used for H. pylori?

Answer 19

(1) clarithromycin, amoxicillin, PPI
(2) clarithromycin, metronidazole, PPI
(3) levofloxacin, metronidazole, PPI, bismuth subsalicylate

Question 20

What can be done for patients with PUD that need NSAID therapy?

Answer 20

(1) concomitant PPI
(2) concomitant PGE analogue
(3) possibly coxibs (provided low CVD risk)

Question 21

What is the PGE2 analogue of choice for PUD?

Answer 21

Misoprostol.

Question 22

What are adverse effects of misoprostol?

Answer 22

(1) bloating, diarrhea

(2) abortifacient

Question 23

How do PGE2 analogues offset NSAIDs?

Answer 23

They protect against gastric ulcers and hemorrhage.

Question 24

Chemically, what is sucralfate?

Answer 24

A complex salt of sucrose sulfate and aluminum hydroxide.

Question 25

What is the MoA of sucralfate?

Answer 25

It binds to the surface of GI mucosa, stimulating mucus, bicarbonate, and PGE2 production.