Urinary phospholipids excretion in neonates treated with amikacin

Aminoglycosides, among the most commonly used antibiotics in neonates, have frequently been implicated in nephrotoxic reaction. Studies in adults have indicated that phospholipiduria (PLU) is rapidly increased during aminoglycoside therapy, in relation to the renal phospholipidosis these drugs are known to induce in renal cortex. We studied the effect of amikacin (AK) on PLU in male prematurely-born neonates (gestational age > 34 weeks; postnatal age < or = 2 days) by assessing the urinary excretion of 4 enzymes (N-acetyl-beta-D-glucosaminidase [NAG], alkaline phosphatase, tau-glutamyltransferase and alanine aminopeptidase) and 4 low-molecular-weight proteins (beta-2-microglobulin, clara cell protein, microalbumin and retinol-binding protein) which are currently used to monitor the development and extent of renal tubular damage. Twenty-two patients and 8 healthy (as control) neonates were enrolled in the study. Patients were treated with AK (15 mg/kg per day) given in one (qd, n = 10) or two equal injections (b.i.d., n = 12) for durations of 7-11 days. PLU and proteinuria were determined in 24-h urine sample collections, and enzymes were assessed in spot urine collected at 9 a.m. We found that in neonates, AK causes a significant increase in PLU, and in enzymuria except for NAG in the qd group. Proteinuria showed no significant change due to AK treatment. No significant differences were observed between qd and b.i.d. administrations of AK for all parameters tested. We conclude that PLU could be used in neonates as well as in adults as a non-invasive method to monitor the development of the renal phospholipidosis during aminoglycoside therapy.