Bleomycin disposition in children with cancer

Bleomycin kinetics were determined in 14 children after intravenous bolus and prolonged infusion doses. Plasma and urine bleomycin concentrations were determined by radioimmunoassay. After intravenous bolus, bleomycin concentrations were adequately described by a two-compartment open model with a mean t 1 2_α and t 1 2_β of 0.3 ± 0.1 and 3.2 ± 0.7 hr (mean ± SEM). Volume of the central compartment and volume of distribution at steady-state (V_ss) were 4.3 ± 0.5 and 9.9 ± 1.1 l/m². Total plasma (CL_T) and renal (CL_R) clearance were 51.8 ± 6.1 and 33.5 ± 2.4 ml/min/m². Three intravenous bolus courses were given to two patients who received more than four courses of cisplatin (>300 mg/m²); CL_T and CL_R for these courses were 18.0 ± 3.3 and 8.2 ml/min/m². Conversely, children under 3 yr old eliminated bleomycin more rapidly than older children. Decline in bleomycin concentrations after seven 24-or 48-hr intravenous infusions was described by a one-compartment model. Mean values for plasma t 1 2, V_ss, CL_T, and CL_R were 2.1 ± 0.1 hr, 11.0 ± 2.6 1/m², 57.1 ± 13.5 ml/min/m², and 33.2 ± 6.4 ml/min/m². One patient received his bleomycin infusion when ureteral obstruction was present; CL_T and CL_R for this course were 4.8 and 4.1 ml/min/m². These data indicate that young children eliminate bleomycin more rapidly than older children and that children with impaired renal function may have prolonged elevations in plasma concentration due to reduced bleomycin clearance. Bleomycin disposition in older children is as in adults.