Suppression of ventricular ectopic depolarizations by tocainide.

Abstract

Patients (12) with stable VED[ventricular ectopic depolarizations] were given loading doses of tocainide (400-600 mg) with maintenance doses every 12 h. Every 48 h the dose was increased until arrhythmia suppression to < 25% of VED frequency during placebo administration or side effects occurred. Computer analysis of 12 h telemetric ECG taken 24-36 h after each dosage increment documented effective suppression (76-95%) in 8 of 12 patients. Those subjects demonstrating suppression were randomly assigned to a cross-over study of placebo or active drug at the dosage found effective in the dose-ranging phase. Dosages for the cross-over stage ranged from 400-1100 mg every 12 h. Comparison of the 2 five-day periods documented suppression in these patients (mean .+-. SE = 83.3 .+-. 4%). No serious side effects or undue drug accumulation occurred during the study. Tocainide apparently can effectively suppress VED for 8-12 h in many patients, and continuous suppression may be possible on an 8-12 h dosage regimen.