PHARMACOKINETIC ANALYSIS OF GENTAMICIN THRICE AND SINGLE DAILY DOSAGEIN PEDIATRIC CANCER-PATIENTS

Fifty-two children suffering from different types of malignancies were included and evaluated for the pharmacokinetics of gentamicin thrice or single daily dosage protocols. All the study population received a total dose of 5 mg/kg daily. Thirty children received gentamicin thric e daily, and 22 were treated using the single daily protocol; all had fever and neutropenia when included. The individual pharmacokinetic pa rameters were calculated using a one-compartment model for two blood g entamicin samples. The mean (SD) t(1/2) (h), clearance (mL/min)BSA), ( L/kg), C-max (mu g/mL), and C-min (mu g/mL) were 3.05 (1.0) and 3.9 (0 .6) h, 136 (61.3) and 99.9 (65.3) mL/min/BSA, 0.4035 (0.167) and 0.457 (0.17) L/kg, 5.2 (2.0) and 11.5 (4.2) mu g/mL, 0.8 (0.6) and 0.18 (0. 1) mu g/mL for thrice and single daily dosage schedules, respectively. The single gentamicin daily dose protocol had a significantly longer t(1/2), shorter clearance normalized to BSA, higher C-max, and lower C -min in comparison with the thrice daily schedule. We recommend the us e of gentamicin at 5 mg/kg daily delivered as a single daily dose for pediatric cancer patients with fever and neutropenia, in spite of the measured pharmacokinetic differences, which in our opinion have no cli nical significance.