Combination of disopyramide and mexiletine for better tolerance and additive effects for treatment of ventricular arrhythmias.

The efficacy and tolerance of disopyramide and mexiletine used alone and in combination were studied in 21 patients with frequent (greater than or equal to 30/h) ventricular premature complexes. Ambulatory electrocardiographic monitoring was performed at baseline and during therapy with disopyramide alone, mexiletine alone and a combination of disopyramide and mexiletine. During single drug therapy, the dose of disopyramide was 602 +/- 152 mg/day and that of mexiletine was 738 +/- 144 mg/day. During combination therapy with smaller doses of disopyramide (524 +/- 134 mg/day) and mexiletine (652 +/- 146 mg/day), no patient had side effects. At baseline before therapy, the mean number of ventricular premature complexes per hour, was 608 +/- 757, of couplets per hour was 22.4 +/- 45.8 and of episodes of nonsustained ventricular tachycardia/24 h was 219.7 +/- 758.2. The mean number of ventricular premature complexes per hour was reduced to 156 +/- 217 with disopyramide alone, 188 +/- 298 with mexiletine alone and 76 +/- 144 with combination therapy (p less than 0.05 for combination therapy versus disopyramide or mexiletine alone; p = NS for disopyramide versus mexiletine). Individually, an effective regimen (greater than 83% reduction in ventricular premature complexes and abolition of nonsustained ventricular tachycardia) was found in 5 (24%) of 21 patients during therapy with disopyramide alone, in 3 (14%) receiving mexiletine alone and in 13 (62%) receiving combination therapy (p less than 0.05 for combination therapy versus disopyramide or mexiletine; p = NS for disopyramide versus mexiletine). Thus, the antiarrhythmic effects of disopyramide and mexiletine are additive.(ABSTRACT TRUNCATED AT 250 WORDS)