[Effect of allapinin after a single intravenous administration to patients with chronic ventricular extrasystole].

Clinical assessment of a new antiarrhythmic drug, allapinin, was carried out in 42 patients with chronic ventricular extrasystoles. Single intravenous doses were effective where they exceeded 0.32 mg/kg. Doses above 0.42 mg/kg were regularly associated with side effects, such as dizziness or, less commonly, diplopia. The 0.39 mg/kg dose produced an antiarrhythmic effect in 61% of patients, whose PQ interval was lengthened by 23%, and the QRS complex, by 18%, while QTc duration remained unchanged. Heart rate and arterial blood pressure were virtually unchanged, either. The peak of antiarrhythmic effect fell to the second postadministration hour, and the effect persisted within an average of 7.6 hours. Therefore, allapinin appears to be a potent quinidine-like agent.