[Anti-arrhythmia effectiveness and tolerance of retard in comparison with standard mexiletine]

In a controlled randomized cross-over trial, 21 patients with coronary artery disease and frequent ventricular arrhythmias were studied to test the efficacy and tolerance of mexiletine 200 mg t.i.d. in comparison to a released application form of mexiletine perlongettes 360 mg b.i.d. During 24-hour Holter monitoring, all patients but one showed more than 30 ventricular premature beats/h; additionally, in 16 patients, complex ventricular arrhythmias (Lown class IV) were documented. In all patients each medication was given for 5 days. Before treatment and during both medication periods, a 4 days' wash-out period was interposed. Mexiletine and mexiletine perlongettes each resulted in a suppression of ventricular ectopy of more than 84% in 10/21 patients (47%); in two patients the response was different. The mean reduction rate in all patients was 68% for mexiletine and 64% for mexiletine perlongettes. In the responder group, the mean reduction rate amounted to 95% under both medications. Ventricular pairs and tachycardia were reduced by more than 90%. Plasma concentration under mexiletine perlongettes was slightly higher, as compared to the standard form of mexiletine; however, under mexiletine, significant changes of plasma concentration were observed during the day only when the standard form was used. Side effects were observed in 8/21 patients (38% for mexiletine) and in 5/21 patients (24% for mexiletine perlongettes). These were mainly gastrointestinal or neurological, but were mild in all patients and did not necessitate discontinuation of the medication in any patient.(ABSTRACT TRUNCATED AT 250 WORDS)