Logical approach to lignocaine therapy.

Plasma lignocaine concentrations were measured during and after lignocaine infusions administered for suppressing ventricular dysrhythmias. Twenty-four patients with a primary diagnosis of acute myocardial infarction without gross circulatory disturbance received, after a bolus of lignocaine, either 4 mg/min for 30 minutes, 2 mg/min for two hours, then 1 mg/min thereafter or 1 mg/min throughout. The higher dose regimen produced continous therapeutic levels of lignocaine, which were achieved only after four hours by the lower dose. On the other hand, in patients who had undergone cardiac surgery and who had circulatory and heptic dysfunction the lower dose regimen achieved therapeutic levels early. The plasma half life was longer in the surgical group (P less than 0.02). The higher initial infusion rate is recommended for patients with acute myocardial infarction without gross circulatory impairment.