Pharmacokinetics of levamisole in healthy subjects and cancer patients.

Abstract

Eleven healthy volunteers (six men, five women) and twelve cancer patients (six men, six women) were given single oral doses (2.5 mg/kg body weight) of levamisole, an immunostimulant agent. In a second experiment eleven healthy et volunteers (six men, five women) and twelve cancer patients (six men, six women) were given single oral doses (5 mg/kg body weight) of levamisole. The levamisole concentrations in plasma (24 h blood sampling) were measured by gas chromatography after extraction. A mono-compartment open model was proposed, and some parameters were calculated. The main results from these two experiments are: the drug was absorbed well, the peak levels of levamisole in the plasma were reached after 1.0 – 2.0 hrs and ranged between 0,8 (μg and 1.6 μg/ml with the 2.5 mg and 5 mg/kg body weight doses respectively (concentrations requiredin vitro to produce an immunological effect); the plasma half-life of levamisole calculated from the decline in the concentration curves varied between 3.3 h and 5.1 h; the absorbed fractions were 0.7 and clearance 310 ml/min; twenty-four hours after medication, the levamisole concentrations in plasma were only 6 % of the peak levels.