A case of ranitidine-induced bradycardia

Ranitidine, a selective histamine-2 antagonist, may seldom cause bradycardia. A 28-year-old male patient was admitted with high fever, nausea, vomiting, headache, and joint tenderness. He was conscious and in good general status. His temperature was 38.4 °C, pulse rate was 84/min, and blood pressure was 100/60 mmHg. He had a history of vasovagal syncope. Treatment was instituted for infection and fever. His temperature became normal on the second day. On the third day, the patient complained of stomach ache. Intravenous ranitidine was administered on the fourth day, after which heart rate decreased to 30/min. His temperature was 36.4 °C and blood pressure was 110/70 mmHg. Electrocardiographic (ECG) monitoring was instituted in the intensive care unit, at which time he was in sinus rhythm with a heart rate of 34/min. During ECG monitoring heart rate ranged from 28/min to 35/min. Upon discontinuation of ranitidine, heart rate returned to normal on the ninth day.