Clinical evaluation of the antiarrhythmic properties of intravenously administered mexiletine: Efficacy comparison with lidocaine in a crossover randomized trial

Thirty patients with stable ventricular arrhythmias participated in a cross-over study based on intravenous mexiletine and lidocaine for three consecutive days. Efficacy was assessed by long-term tape recordings of electrocardiogram. After a two-hour control period, the patients received one of the two drugs, according to a randomized scheme, for 24 hours. Then, a wash-out period of 22 hours was allowed, followed by a second control period of 2 hours. Afterwards, a cross-over to the other drug was performed. Both drugs reduced significantly the number of ventricular extrasystoles per minute but the reduction induced by mexiletine was more marked (86 ± 6% versus 68 ± 5%, p <0.05). Arrhythmia control (greater than 75% reduction of premature ventricular complexes) was achieved in 27 trials with mexiletine and 25 with lidocaine. No significant difference between the two drugs was observed in the incidence of adverse reactions. These results indicate that mexiletine is at least as effective and safe as lidocaine for suppression of ventricular arrhythmias and may be useful also in some cases of lidocaine-resistant dysrhythmias.