Increased dosage requirements of gentamicin in burn patients.

In 14 burn patients treated for serious Gram-negative infections, the use of the previously recommended gentamicin dose of 5 mg/kg/day was found to result in subtherapeutic serum concentrations (peak concentration less than 4 mg/L). The gentamicin half-life was found to be unusually short especially in the younger burn patients. Because of this shorter half-life the dosage interval was decreased to 4 hours to prevent extended periods of subtherapeutic serum concentrations. In addition, the daily dose of gentamicin was increased to achieve therapeutic peak concentration. Individualizing each patient's gentamicin regimen was thought to be instrumental in the favorable response of two patients with Pseudomonas ecthyma gangrenosum. The results of this study would strongly support the measurement of serum gentamicin levels in all burn patients with life-threatening infection. The gentamicin dosage regimen should then be individualized for each patient to provide optimal peak concentrations. In addition, patients demonstrating a short drug half-life may require a decreased dosage interval to prevent prolonged periods of sub-therapeutic concentrations.