GI Pharmacology

Question 1

Drug Therapy for GERD and PUD

Answer 1

H2 receptor antagonists 
Proton pump inhibitors
Mucosal Protectants
Antacids
Antiemetics

Question 2

Upper GI Distress: Increasing Protective Factors

Answer 2

Antacids
Sucralfate

Protective Factors:
Mucus
Bicarbonate
Blood flow
Prostaglandins

Question 3

Upper GI Distress: Decreasing Aggressive Factors

Answer 3

Treating H. pylori
H2 Blockers
Proton Pump Inhibitors

Aggressive Factors:
H. pylori
NSAIDS
Acid
Pepsin
Smoking

Question 4

Treating H. Pylori

Answer 4

Requires several antibiotics W/ gastric acid inhibitor

Question 5

Why a combo therapy for H. pylori?

Answer 5

Minimize resistance, H. pylori likes acidic environment

Question 6

Length of Rx for H. pylori

Answer 6

10-14 days

Adherence: $200 w/ up to 12 pills

Question 7

2 types of drugs to decrease gastric acid production

Answer 7

1. Block H2 receptors (formoterol)

2. Inhibit proton pump (PPI)

Question 8

H2 Receptor Antagonists

Answer 8

cimetidine (Tagamet)

famotidine (Pepcid)

Question 9

H2 receptor antagonists MOA

Answer 9

• Blocks H2 receptors in the stomach
• Blocks gastric acid secretion by 60-70%
• Increases stomach pH

Route: PO, IV
-Give one hour apart from antacids

Question 10

Indications for H2 Receptor Antagonists

Answer 10

GERD
PUD
Ulcer prophylaxis
Heartburn/dyspepsia

Question 11

H2 Adverse Effects

Answer 11

Well tolerated
CNS effects in elderly
Slight Inc risk for PNA in elderly

Question 12

H2 receptor Interactions

Answer 12

• Inhibit CYP 450 enzymes
• Newer generation H2RAs do not have this problem (Pepcid)

Safety alert:

• Can decrease levels of WARFARIN, phenytoin, theophylline
• Give IV form slowly to avoid bradycardia

Question 13

PPI MOA

Answer 13

-Binds to Proton Pump

-Inhibits the hydrogen
potassium ATPase enzyme system (proton pump)

• Irreversibly inhibits the secretion of HCL
• MORE effective than H2RA

Question 14

PPI indications

Answer 14

Short term use:
PUD
GERD

Question 15

PPI Adverse Effects

Answer 15

Short-term: Safe
Long-term: Inc risk for PNA, Bone loss/Hip fx, stomach CA

Few drug interactions

Nursing: short-term only

Question 16

Sucralfate (Carafate)

Answer 16

Class: Mucosal protectant

Unique drug composed of:

• sucrose-base
• Aluminum hydroxide

Question 17

Sucralfate (Carafate): MOA

Answer 17

• Alters when exposed to gastric acid
• Sticky, thick gel (protective barrier)

Indications: Duodenal ulcers (FDA approved) Gastric ulcer (Not FDA approved)

Question 18

Sucralfate (Carafate): AE and Route + interactions

Answer 18

PO (tab or suspension)

AE: no major, constipation

Interactions:

• DECREASED DRUG ABSOPTION
• PO: take 2 hours apart

Question 19

Antacids

Answer 19

Aluminum (Amphojel)
SE: constipation

Magnesia (MOM)
SE: diarrhea

Calcium (TUMS)
SE: constipation

Aluminum + Mg (Maalox, Mylanta)
SE: balanced approach

Question 20

Antacids MOA

Answer 20

Neutralize acid by 50%

Question 21

Antacid Indication

Answer 21

PUD
GERD
Stress ulcers
Heartburn + Indigestion

Question 22

Antacid Adverse Effects

Answer 22

Diarrhea + Constipation
Acid rebound

Interactions:

• Chelation
• Altered gastric absorption of many drugs
• Separate other drugs by 1 to 2 hours