GI Pharmacology

Question 1

Treating H. pylori

Answer 1

-Several ANTIBIOTICS + gastric acid inhibitor
-Why combination therapy?Minimize resistance, H. pylori likes acidic environment
-Length of Rx: 10 – 14 days
-Adherence? About $200 with up to 12 pills

Question 2

WHAT ARE THE TWO WAYS DRUGS TARGET GASTRIC ACID PRODUCTION?

Answer 2

1. BLOCK H2 receptors
2. INHIBIT Proton Pump

Question 3

H2 Receptor Antagonists: Drugs

Answer 3

-cimetidine (Tagamet)
-famotidine (Pepcid)

Question 4

H2 Receptor Antagonists: MOA

Answer 4

◦ Block H2 receptors in the stomach
◦ Reduces gastric acid secretion by 60-70%
◦ Increases stomach pH

Question 5

H2 Receptor Antagonists: Route and Indications

Answer 5

Route: PO, IV
◦ Give at least 1 hour apart from antacids

Indications: GERD, PUD, ulcer prophylaxis, heartburn/dyspepsia

Question 6

H2 Receptor Antagonist: Adverse Effects and Considerations

Answer 6

Adverse Effects
◦ Well tolerated
◦ CNS effects in elderly
◦ Slight ↑ risk for pneumonia in elderly

Interactions
◦ Inhibits CYP450 enzymes (older agents)
◦ Newer generation H2RAs do not have
this problem (ex. Pepcid)

Safety Alert
◦ Can increase levels of warfarin, phenytoin, theophylline
◦ Give IV form slowly to avoid bradycardia

Question 7

Proton Pump Inhibitor (PPI): Drugs

Answer 7

-omeprazole (Prilosec)
-pantoprazole (Protonix)
-esomeprazole magnesium (Nexium)

Question 8

Proton Pump Inhibitor (PPI): MOA

Answer 8

Binds to proton pump
-Inhibits the hydrogen potassium ATPase enzyme system (proton pump)
-Irreversibly inhibits the secretion of HCl

o More effective than H2RA

Question 9

Proton Pump Inhibitor (PPI): Indications

Answer 9

Short term treatment of PUD
and GERD