Nausea, vomiting, diarrhea, constipation and rash are the more frequently encountered adverse reactions of ranitidine – a selective histamine H2 receptor antagonist. Only a few cases of cardiovascular side effects have been reported [1-3].

A 10-year-old boy was admitted to our hospital for percutaneous endoscopic gastrostomy (PEG). He had had neurological disability because of neonatal　bilirubin encephalopathy. He was receiving diazepam and baclofen dystonia for last six years. Laboratory examination, including whole blood count, blood chemistry results, and thyroid function tests were normal. Percutaneous endoscopic gastrostomy (PEG) tube was inserted. Ranitidine was injected at a dose of 4 mg/kg/day in four divided doses by intravenous route starting from 24 hour after the procedure. After four hours of the first dose of ranitidine, the child was noted to have bradycardia (HR 60/min) and the blood pressure fell to 80/50 mmHg 16 hours after the first dose of ranitidine. At the third day of ranitidine treatment, the heart rate was detected to be 36/min and there was common voltage drop on electrocardiography. Echocardiography was normal. Physical examination revealed no additional findings except bradycardia and hypotension. Ranitidine treatment was stopped. No treatment was given for bradycardia and hypotension because of the good general condition of the patient. Heart rate and blood pressure improved after 12 hours of discontinuation of ranitidine.

H2 receptors are reported to be present in sinus node, atrial and ventricular myocardium as well as gastric mucosa [1]. Cimetidine and ranitidine have been reported to cause significant hypotension in critically ill patients. Though gastric interventions such as PEG insertion may lead to increased vagal tone causing bradycardia, it was not seen until the first dose of ranitidine treatment in present case. Moreover, it resolved following cessation of ranitidine treatment.

Clinicians should always be aware of the possibility of rare but potentially serious cardiovascular adverse events of ranitidine, especially in sick children.

1. Vial T, Goubier C, Bergeret A, Cabrera F, Evreux JC, Descotes J. Side effects of ranitidine. Drug Saf. 1991;6:94-117.

2. Yang J, Russell DA, Bourdeau JE. Case report: ranitidine-induced bradycardia in a patient with dextrocardia. Am J Med Sci. 1996;312:133-5.

3. Smith CL, Bardgett DM, Hunter JM. Haemodynamic effects of the i.v. administration of cimetidine or ranitidine in the critically ill patient. A double-blind prospective study. Br J Anaesth. 1987;59:1397-402.