Flecainide and cardiac dysrhythmias during dental extraction under anaesthesia.

In a randomized double-blind study, either oral flecainide acetate 400 mg (a Class IC anti-dysrhythmic drug) or placebo was given in two divided doses 12 and 2 h pre-operatively to 38 patients undergoing outpatient molar extractions under halothane anaesthesia. The ECG was continuously monitored from the patients' arrival at the out-patient theatre until discharge, using a two-channel ambulatory magnetic tape recorder. There was a much lower incidence of ventricular dysrhythmias in patients who received flecainide (22%) than those who received placebo (75%) (P less than 0.05). In addition, dysrhythmias were both more severe and more prolonged in the untreated group, prompting treatment with intravenous practolol in seven patients (35%). Flecainide was well tolerated and no adverse effects were reported.