Bleomycin pharmacokinetics in man

Summary

Bleomycin plasma decay kinetics and urinary excretion were studied in nine patients after IV bolus injections of 13.7 to 19.9 U/M². Radio-immunoassay was used to measure bleomycin in plasma and urine samples. The resulting plasma concentration versus time data for each patient and the combined data obtained from all patients were fitted to a multiexponential equation using a nonlinear regression computer program. Pharmacokinetic parameters derived from the mean of all individual patient parameters and the composite of all plasma decay data were similar. Bleomycin initial and terminal plasma half-lives and volume of distribution for all plasma decay data from eight patients with normal serum creatinies were 24.4±4.0 min, 237.5±8.5 min, and 17.3±1.5 L/M², respectively. Mean 24-h urinary excretion accounted for 44.8±12.6% of the dose in seven patients who had normal serum creatinine values and complete urine collections. The total body clearance and renal clearance in these seven patients averaged 50.5±4.1 ml/min/M² and 23.0±1.9 ml/min/M², respectively. One patient with a serum creatinine of 1.5 mg% (normal 0.7 to 1.3 mg%) who was given 15.6 U/M² had a terminal plasma halflife of 624 min, a volume of distribution of 36.3 L/M², and 24-h urinary excretion of 11.6% of the dose. We conclude that bleomycin after intravenous bolus injection has a relatively short terminal phase plasma halflife and relatively large urinary elimination.