Antiarrhythmic efficacy of pirmenol in the treatment of premature ventricular complexes

Abstract
We assessed the antiarrhythmic effectiveness, therapeutic plasma concentrations and adverse effects of pirmenolin 16 patients with frequent (mean 933 h−l) premature ventricular complexes (PVC). Progressive increase in dose to a maximum of 200 mg twice daily suppressed PVC in a majority of patients. By preset criteria 11 patients (69%) exhibited an effective suppression of PVCs whereas in 5 patients (31%) the suppression was inadequate despite therapeutic plasma concentrations. The responders exhibited an 87% mean reduction of PVCs and a 97% reduction in repetitive PVC. This therapeutic effectiveness was verified against placebo by repetitive 24-hour ECG monitorings recorded in a double-blind cross-over fashion. The plasma trough concentration during the effective dose averaged 1.31±0.67 mg−1 (SD). The efficacy was maintained with the twice daily regimen despite an elimination half life of6.3±1.7h (SD) but a slight decrease in PVC suppression was observed towards the end of the administration interval. Pirmenol was well tolerated but aggravation of the arrhythmia occurred in one patient who shared an associated excessive prolongation of the Q-T interval, a feature observed with quinidine-like class I agents.