Cifenline in the short-term treatment of patients with ventricular premature complexes: a double-blind placebo-controlled study.

To study the efficacy and safety of cifenline (cibenzoline), a new antiarrhythmic agent, we enrolled 46 patients with greater than 700 premature ventricular complexes (VPCs)/24 h in an ambulatory electrocardiography study. During an open-label titration phase, 25 patients showed greater than 75% VPC suppression while receiving 130 mg (15 patients) or 160 mg (10 patients) cifenline twice daily. During a double-blind placebo-controlled phase in 23 of these patients, cifenline was more effective than placebo in controlling VPCs (p less than 0.0001) and VPC pairs (p less than 0.025). A small (0.01 s) increase in QRS duration was observed (p less than 0.05) during cifenline treatment. Adverse experiences included gastrointestinal complaints and dizziness as well as two instances of hypotension and one instance of symptomatic ventricular tachycardia. Cifenline appears to be effective and well tolerated in the treatment of VPCs.