Intravenous lorcainide versus lidocaine in the treatment of frequent and complex ventricular arrhythmias.

Thirty patients with frequent (greater than or equal to 30/hr) and repetitive ventricular premature beats (VPBs) unassociated with acute infarction were randomized to intravenous lorcainide (LOR) or lidocaine (LID). Following at least 2 hours of baseline Holter monitoring, patients received LOR, 2 mg/kg then 200 mg/24hr, or LID, 1 mg/kg then 2 mg/min, with rebolus if needed. Nonresponders detected by bedside telemetry were crossed over. Clinical response was 6 of 25 (24%) including two of nine crossovers with LOR and 8 of 26 (31%) including 3 of 12 crossovers with LID (p = NS). By computer analysis of 24-hour Holter monitors and asymptotic regression of success rates at hourly intervals, it was projected that greater than or equal to 80% reduction in VPBs occurred in 28% of LOR and in 25% of LID (p = NS), and complete suppression of repetitive VPBs occurred in 102% of LOR and in 92% of LID (p = NS). The mean drug levels were 405 ng/ml (range 371 to 463) with LOR and 3.4 micrograms/ml (range 2.1 to 3.6) with LID. Side effects were similar, occurring in 8 of 25 LOR trials and in 11 of 26 LID trials (p = NS). Thus, LOR and LID effectively suppress repetitive VPBs and to a lesser extent VPB frequency. However, neither drug is superior and each may be an effective alternative when resistance to the other is encountered.