Abstract
Urinary concentrations of NAG reflect nephrotoxicity and are generally expressed per mg creatinine (Cr). We studied the time course of G-induced renal effects in 22 neonates of 32-36 wks gestational age. Gp A (n=13) received G; Gp B (n=9) otherwise comparable but not requiring G served as controls. Timed urine collections started on day of first G treatment (Gp A) or on admission (Gp B). NAG, β2-microglobulin (β2-M) and Cr were assayed.
NAG increased within 11-25 h of starting G and decreased to control 2-3 days after cessation of G. The pattern with β2-M was similar. The rapid decline of NAG following cessation of G suggests that de novo exposure to the drug is more important in inducing enzymuria than is persistence of G in renal tubular cells. Urinary Cr was not different between Gps (p>0.2), but rose with postnatal age (PNA):0.015±0.002 mg/min (PNA 1 day); 0.017±0.002 (PNA 3 days); 0.028±0.004 (PNA 4-7 days). Serial values of NAG/mg Cr were also greater in Gp A (p<0.01). Although age-related increase in U Cr was not a problem with serial evaluations as described here, in analysis of subtle differences in comparative drug studies, timed output of NAG may be a more reliable indicator of nephrotoxicity when studies are not controlled for age.
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Rajchgo, T., Macleo, D., Klei, N. et al. 1533 URINARY N-ACETYL GLUCOSAMINIDASE (NAG) AS AN INDICATOR OF GENTAMICIN (G) NEPHROTOXICITY IN PREMATURE INFANTS. Pediatr Res 15 (Suppl 4), 698 (1981). https://doi.org/10.1203/00006450-198104001-01556
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DOI: https://doi.org/10.1203/00006450-198104001-01556