Indication: Pepcid is a histamine-2 (H2) receptor antagonist indicated in adult and pediatric patients 40 kg and above for the treatment of active duodenal ulcer active gastric ulcer.

Insight:

Dosing: May vary from 20 mg to 40 mg depending on the indication.
Dosage forms: Tablets 20 mg and 40 mg.
Adverse events: The most common adverse reactions are headache, dizziness, constipation, and diarrhea.
Mechanism of action: Famotidine is a competitive inhibitor of H2 receptors. The primary clinically important pharmacologic activity of famotidine is inhibition of gastric secretion. Both the acid concentration and volume of gastric secretion are suppressed by famotidine, while changes in pepsin secretion are proportional to volume output.

Source: label (fda.gov)