Antiarrhythmic and pharmacokinetic evaluation of intravenous recainam in patients with frequent ventricular premature complexes and unsustained ventricular tachycardia

The pharmacokinetics, antiarrhythmic activity and safety of intravenously administered recainam were evaluated in 15 men and 3 women. All patients had frequent (>30/hour) ventricular premature complexes (VPCs) and unsustained ventricular tachycardia. Recainam was administered at a loading dose of 4.5 mg/kg/hour over 40 minutes, followed by a maintenance infusion f 0.9 mg/kg/hour for 23 hours and 20 minutes. Sixteen patients had satisfactory efficacy data. The mean frequency of total VPCs decreased by 92.6% and the mean frequency of runs decreased by 99.9% during the maintenance infusion. Suppressions of [is greater than or equal to] 70% of total VPCs and [is greater than or equal to]90% of runs were maintained over the 23-hour, 20-minute maintenance infusion period in 16 of he 18 patients. During the maintenance infusion, hourly group plasma recainam concentrations ranged from mean [+ or -] SD 2.6 [+ or -] 0.7 to 3.4 [+ or -] 0.9 [mu]g/ml. Patients were observed for 24 hours after termination of the infusion. Periodic blood samples were obtained during and after termination of the infusion to determine recainam concentration. Urine specimens were collected over scheduled intervals to determine urinary excretion of recainam. A 2-compartment pharmacokinetic model was used to analyze the data. The following pharmacokinetic parameters were obtained: terminal elimination half-life, 5.0 [+ or -] 0.8 hours; systemic clearance, 0.27 [+ or -] 0.08 liter/hour/kg; and central and steady-state volume of distribution, 0.32 [+ or -] 0.11 and 1.4 [+ or -] 0.4 liter/kg, respectively. Adverse experiences were reported in 4 of the 18 patients, possibly drug-related in 2; none was considered severe or required discontinuation of recainam. Mean electrocardiographic PR and QRS intervals (but not QTc interval) were prolonged 20 to 25% (p [is less than or equal to]0.01) compared with baseline. No proarrhythmic response to recainam was observed. No clinically significantly changes in vital signs or in laboratory test results occurred. This study suggests that intravenous recainam is highly active in suppressing ventricular ectopy and may be safely administered. However, compete safety profiling and determination of its clinical role require additional studies.