Efficacy of recainam, a new antiarrhythmic drug, for control of ventricular arrhythmias.

The antiarrhythmic efficacy and safety of oral recainam hydrochloride, a newly synthesized compound, were assessed during a 2-part study of 12 patients with frequent (at least 30/hour) ventricular premature complexes (VPCs). During the initial dose-ranging phase, 11 patients with qualifying arrhythmias (median VPC frequency 575/hour, range 37 to 1,494) received incremental oral doses of 100, 300 and 500 mg of recainam given every 8 hours, each for 3 days. Efficacy was assessed on the last day of each dose. The 300-mg/day dose of recainam was generally ineffective; the 900-mg/day dose was partially effective (58% median VPC reduction, p = 0.03); and the 1,500-mg/day dose was very effective (79% reduction, p less than 0.003). Median reductions in repetitive beats (beats in couplets and runs) for the 3 doses were 18% (difference not significant), 94% (p less than 0.01), and 98% (p less than 0.004), respectively. Recainam provided individual efficacy (at least 70% VPCs or at least 90% repetitive beat suppression, or both) in 7 (64%) of the patients taking 900 mg/day and in 8 (73%) taking 1,500 mg/day. Minimum steady-state plasma concentrations were higher in responders (1.8 +/- 0.5 microgram/ml) than in nonresponders (1.0 +/- 0.5 microgram/ml) (p less than 0.05). The electrocardiographic response to recainam (1,500 mg/day) included increases in PR (by 22%, p less than 0.003) and QRS (by 14%, p less than 0.002) intervals and a small decrease in JTc duration (by 9%, p less than 0.04). Radionuclide ejection fraction did not change. Noncardiac adverse reactions were minimal.(ABSTRACT TRUNCATED AT 250 WORDS)