Ranitidine-induced bradycardia in a neonate--a first report.

Bradycardia, an extremely rare side-effect of ranitidine therapy is described in a 4-day-old full-term male neonate, who was admitted because of massive gastro-intestinal bleeding. Two hours after the intravenous injection of 1 mg/kg body weight per day, ECG showed sinus bradycardia of 60 beats/min with normal axis and QRS complex. The bradycardia gradually resolved in the next 24 h.