H2 Receptor Blockers

Histamine-2 receptor blockers are used for the treatment of peptic ulcers, gastroesophageal reflux disease (GERD), and for the prevention of stress ulcers.  Blockage of H2 receptors results in reduced secretion of gastric acid in the stomach.  Cimetidine is metabolized by the CYP450 system, so many interactions with other medications can occur with this medication.  Other medications in this class are not metabolized by the CYP450 system.  Ranitidine was pulled from the market for possible cancer risk.  

Class Drugs

• Cimetidine

• Famotidine

• Nizatidine

• Ranitidine

Class Mechanism of Action

Blocks histamine type 2 receptors

Histamine receptor blockade results in decreased secretion of gastric acid

Class Applications

Peptic Ulcers

Stress ulcer prevention/treatment

GERD

Class Adverse Effects

• Generally well tolerated with the exception of cimetidine

• Ranitidine withdrawn for possible cancer risk

Drug Table

Drug Name	Application	Comments	Image
Cimetidine		Adverse effects; -Gynecomastia; -Inhibits CYP450 enzymes, which interferes with metabolism of warfarin, phenytoin, clopidogrel, etc.; -Confusion in elderly	"Cy Young" "Mets Logo" "Diner"
Famotidine			"Family" "Diner"
Nizatidine			"Nice" "Tea" "Diner"
Ranitidine			"Ran" "Cousin It" "Diner"