[Pharmacokinetics and toxicity of gentamycin in the newborn infant].

Gentamicin, as the other aminoglycosides, has a very narrow therapeutic index. The pharmaco-kinetics parameters in neonates depend on the renal maturation which is a function of post-conceptional age. Using an unit dose of 2 mg/kg and adapted time intervals, longer for premature babies and in the first week of life, the frequency of too high trough levels is decreased. A convenient method is proposed for determining when to reduce the time interval between injections. Audiotoxicity is both cochlear and vestibular and can be, only in part, detected by evoked potentials. Nephrotoxicity is initially, a tubular injury with an increase of enzymuria (NAG) and beta 2 microglobulinuria, followed by alterations of glomerular filtration. Blood concentrations monitoring is indicated in all gentamicin treated neonates.