Commentary: An appraisal of tobramycin usage in pediatrics

Tobramycin is a newly marketed aminoglycoside which closely resembles gentamicin in antimicrobial activity, pharmacology, clinical efficacy, and toxicity. It is somewhat more active in vitro against Pseudomonas aeruginosa than is gentamicin and may have a lower ototoxic potential. Tobramycin should be considered a limited-purpose drug for pediatric patients until greater clinical experience has been gained. At the present time the major indication for its use is for treatment of infections caused by coliforms or pseudomonas resistant to kanamycin and gentamicin. Demonstration of in vitro susceptibility is mandatory because resistance to tobramycin and the other aminoglycosides may be mediated by the same episome (R-factor). The recommended dosage is 2 mg/kg every 12 hours (4 mg/kg/day) intramuscularly or as a two-hour intravenous infusion to neonates, with the possible exception of full-term infants over seven days of age who may require administration every eight hours. Beyond the neonatal period, the dosage should be 1.0 to 1.5 mg/kg every eight hours (3 to 4.5 mg/kg/day). Larger dosages may be required for treatment of meningitis, but presently there is no information on which to base a recommendation. Neither is there experience with intrathecal use in infants. It is desirable to monitor tobramycin serum concentration to be certain that peak values are within the therapeutic range of 3 to 8 mug/ml. Dosage must be reduced in patients with impaired renal function and monitoring of serum concentrations is imperative. All patients should be evaluated for evidence of renal and eighth nerve toxicity.