H2 Antagonists

Question 1

Cimetidine

Answer 1

Class: N/A

Mechanism: H2 receptor antagonist; blocks gastric acid secretion (more so with nocturnal acid secretion than meal secretion)

Thera: Dyspepsia, duodenal and gastric ulcers, hypersecretory conditions

Tox: Antiandrogen (causing impotence and gynecomastia), inhibition of P450 enzymes
CNS dysfunction possible

Misc: Most SEs of H2 blocker class

Question 2

Ranitidine

Answer 2

Class: N/A

Mechanism: H2 receptor antagonist; blocks gastric acid secretion (more so with nocturnal acid secretion than meal secretion)

Thera: Dyspepsia, duodenal and gastric ulcers, hypersecretory conditions

Tox: Liver tox
CNS Dysfunction possible

Question 3

Famotidine

Answer 3

Class: N/A

Mechanism: H2 receptor antagonist; blocks gastric acid secretion (more so with nocturnal acid secretion than meal secretion)

Thera: Dyspepsia, duodenal and gastric ulcers, hypersecretory conditions

Tox: CNS Dysfunction possible

Question 4

Nizatidine

Answer 4

Class: N/A

Mechanism: H2 receptor antagonist; blocks gastric acid secretion (more so with nocturnal acid secretion than meal secretion)

Thera: Dyspepsia, duodenal and gastric ulcers, hypersecretory conditions

Tox: CNS dysfunction possible

Misc: Least side effects of H2-blocker class