Amikacin pharmacokinetics in pediatric patients with malignancy.

The pharmacokinetics of amikacin were evaluated in 50 pediatric patients (1 to 17 years of age) with malignancies and normal renal function. Dosage regimens of 5 mg/kg per dose were administered intravenously (i) over 30 min every 8 h, (ii) over 60 min every 8 h, and (iii) over 60 min every 6 h. Administration of amikacin over 30 min produced concentrations in serum of 29.3 +/- 5.7 micrograms/ml at the end of the infusion and subtherapeutic concentrations 4 h after the infusion. The regimen of 20 mg/kg per 24 h, divided into doses given every 6 h infused over 60 min, achieved concentrations in serum at the end of the infusion of 17.2 +/- 1.7 micrograms/ml and at 6 h of 1.2 +/- 0.3 microgram/ml. The serum half-life was 1.24 +/- 0.09 h, volume of distribution was 0.26 +/- 0.02 liter/kg, and total body clearance rate was 131 +/- 10 ml/min per 1.73 m2. No accumulation of amikacin was noted, and no significant side effects could be attributed to the drug. This study suggests that the optimal initial dosage regimen of amikacin in children is 20 mg/kg per 24 h administered in equal doses every 6 h over 60 min; however, optimal therapy requires individualization of dosage based on measured serum concentrations and susceptibility data on bacterial pathogens isolated.