Pharmacokinetic study on intravenous drip infusion of gentamicin in pediatrics

We performed a pharmacokinetic study of gentamicin (GM) in 46 children who were given GM by intravenous drip infusion at doses of 0.8, 2.0 and 2.5mg/kg over a period of 30 or 60 minutes. The results are summarized as follows: I. Evaluating by infusion speed and age, we noted a clear dose-dependent response among the three dose groups. Peak blood concentrations tended to increase with age. 2. Intravenous drip infusion of GM at a dose of 0.8mg/kg did not achieve a therapeutically effective peak concentration of 4μg/ml in most children. At a dose of 2.5mg/kg, 2 children had peak blood concentrations greater than 12μg/mI, a possibly toxic dose. 3. Reviewing trough concentrations, we found concentrations of less than 2μg/ml in all children, indicating that no drug accumulation occurs. 4. Multiple administration of GM produced no elevation in peak and trough concentrations. 5. The cumulative urinary recovery rate up to 6 hours after administration was approximately 52.9%. 6. Reviewing the pharmacokinetic parameters obtained, we found that elimination rate constants increased, and half-life values decreased with age. Also, the distribution volume decreased, while clearance values tended to increase with age. The above results indicate that an intravenous drip infusion of GM at a dose range of 2.0-2.5 mg/kg over a period of 30-60 minutes is a form of administration recommended for the treatment of children.