CLINICAL PHARMACOKINETICS OF ANTI-ARRHYTHMIC AGENT CHANGROLIN

Changrolin is a new anti-arrhythmic agent. An intravenous drip of changrolin (55 μg/kg/min) for 60 rain was given to 11 patients with arrhythmia. The peak concentration was 3.6+0.6 μg/ml plasma at the end of the iv drips. Except in 3 patients with node premature beats, the premature ventricular beats (PVBs) were completely suppressed in 8 patients at 26±9 min after start of the medication, and the effective plasma concentration of changrolin was 2.6±0.7 μg/ml. However, the PVBs reappeared when changrolin level lowered to 2.0±0.6 μg/ml in plasma. The pharmacokinetic characteristics of changrolin were found to fit a one-compartment open model. The pharmacokinetic parameters were: elimination rate constant K=0.032±0.011 min^-1; t_1/2=24±13 min; the volume of distribution (Vd) = 0.43 ± 0.19 L/kg.The blood pressure and ECG were not changed remarkably at a range of 2.7～3.2 μg/ml of changrolin concentration in plasma after an initial bolus of changrolin 50 mg was injected to 6 healthy volunteers, followed by an iv drip of 40 μg/kg/min for 55 min.