Acute, single, intravenous doses of cibenzoline: an evaluation of safety, tolerance, and hemodynamic effects.

Abstract

Cibenzoline is a new antiarrhythmic agent with predominant Vaughan-Williams type 1 properties. The safety, tolerance, and adverse effects of incremental single intravenous doses of this agent were investigated. A total of 28 patients received incremental doses of 0.25 mg/kg (four patients), 0.5 mg/kg (five patients), 0.75 mg/kg (seven patients), 1.0 mg/kg (six patients), or 1.2 mg/kg (six patients) cibenzoline. Another six patients received 2.0 mg/kg disopyramide. Left ventricular function by radionuclide ventriculography and plasma cibenzoline levels were measured at frequent intervals. In the patients who received 1.0 mg/kg and 1.2 mg/kg cibenzoline or patients who received 2.0 mg/kg disopyramide, right and left ventricular filling pressures and cardiac output were measured with a Swan-Ganz catheter. At low-dose cibenzoline (0.25 to 0.75 mg/kg) there was a modest drop in ejection fraction (60% +/- 7% to 53% +/- 7%). With the higher doses of cibenzoline (1.0 or 1.2 mg/kg) there was a more profound fall in ejection fraction (69% +/- 8% to 49% +/- 8%) that persisted for approximately 2 hours. This was associated with a rise in end diastolic volume index (74 +/- 24 to 85 +/- 27 ml/m2) and end systolic volume index (29 +/- 15 to 43 +/- 18 ml/m2) and a fall in cardiac index (2.65 +/- 0.62 to 2.14 +/- 0.24 L/min/m2).(ABSTRACT TRUNCATED AT 250 WORDS)