[Pharmacokinetics and Antiarrhythmic effects of Prajmalium Bitartrate]

8 patients with ventricular premature contractions were treated with prajmalium bitartrate (Neo-Gilurytmal) 20 mg q.i.d. The electrocardiograms were continuously monitored by a computerized arrhythmia monitoring system. For definition of the drug's pharmacokinetic properties plasma concentrations were determined. 7 patients showed a marked arrhythmia reduction. Mean ventricular premature contraction frequency was significantly reduced 6 h after onset of treatment, maximum arrhythmia suppression to 34% of control was observed after 24 h of treatment. The correlation of antiarrhythmic response and plasma concentrations was good. Mean plasma concentrations during steady state conditions were 218 ng/ml. Plasma half-life was determined 7.3 h. The lower limit of therapeutic plasma concentrations was between 43 and 145 ng/ml. A mean total clearance of 344 ml/min indicates a low hepatic extraction of prajmalium bitartrate. Moreover, the distribution volume of 204 l suggests a high tissue affinity of the drug.