ranitidine /ranit″idēn/ , a histamine H2 receptor antagonist. 
INDICATIONS: It is prescribed in the treatment of gastroesophageal reflux disease and gastric hypersecretory conditions. CONTRAINDICATIONS: Known sensitivity to this drug prohibits its use. The drug should be used in pregnancy only if clearly needed and with caution in those with severe hepatic or renal impairment. ADVERSE EFFECTS: Among the most serious adverse effects are acquired hemolytic anemia, agranulocytosis, atrioventricular block, agitation, dizziness, headaches, rashes, gynecomastia, and loss of libido.
