Cerebral and cardiac toxicity of a small dose of lignocaine.

A patient is reported in whom an intravenous bolus injection of 50 mg lignocaine produced extreme sinus bradycardia (rate 14 to 20/min). Only 2 patients with such a response to a similarly small dose have been previously reported, but these reports indicate clearly that careful electrocardiographic monitoring is advisable when lignocaine is administered.