ABSTRACT. Objective. Greater use of invasive procedures and aggressive antimicrobial therapy predispose extremely low birth weight (ELBW) infants to systemic fungal sepsis. Despite its adverse effects (including renal and electrolyte disturbances), amphotericin B (amphoB) remains the preferred drug for fungal therapy. Multiple studies have indicated that sodium loading may prevent renal toxicity among animals and human adults. The effects of fluid and electrolyte management on amphoBinduced nephrotoxicity among ELBW infants have not been evaluated extensively. The purpose of this study was to examine the effects of fluid and electrolyte management on amphoB-induced nephrotoxicity among ELBW infants.Design/Methods. The medical records were reviewed for all ELBW infants (birth weights of <1250 g) who developed systemic fungal sepsis, requiring amphoB therapy, between January 1992 and December 2000. Demographic, clinical, and laboratory data were collected from the medical records for each patient.Results. Fungal sepsis requiring amphoB treatment developed for 4.4% of ELBW infants (25 of 573 infants), with a gestational age of 25 ؎ 1 weeks and a birth weight of 738 ؎ 37 g, at a postnatal age of 16 ؎ 2 days. Renal compromise, as manifested by low urine output and high creatinine levels, occurred for 44% of those infants (11 of 25 infants). There was no difference between the infants who developed renal compromise (renal compromise group [RCG], n ‫؍‬ 11) and those who did not (no-renalcompromise group [NCG], n ‫؍‬ 14) with respect to birth weight, gestational age, and risk factors predisposing the infants to fungal sepsis. The RCG demonstrated a decrease in urine output by 3.4 ؎ 2 days and an increase in serum creatinine levels by 3.9 ؎ 2 days after the initiation of amphoB therapy. Infants in the RCG had a significantly higher incidence of hyponatremia, compared with infants in the NCG (7 of 11 infants vs 0 of 14 infants), with no significant difference in the incidences of hypokalemia (2 of 11 infants vs 0 of 14 infants). Infants in the RCG, compared with infants in the NCG, had significantly lower mean daily sodium intakes in the 4 days before the initiation of amphoB therapy (2.6 -2.9 mEq/kg per day vs 4.2-4.7 mEq/kg per day) and in the first 4 days of amphoB treatment (2.7-3.1 mEq/kg per day vs 4.5-5.6 mEq/kg per day). Mean daily sodium intakes were not statistically significantly different between the 2 groups between day 5 and day 10 of amphoB therapy. Infants in the RCG tended to have lower mean daily potassium intakes in the 4 days before the initiation of amphoB therapy and during the first 4 days of amphoB therapy. Subsequently, the mean daily potassium intakes remained not statistically significantly different between the groups. Mean daily fluid intakes were not different between the groups.Conclusions. Conventional amphoB combined with adequate hydration and higher sodium intakes of >4 mEq/kg per day may provide effective protection against amphoB-induced nephrotoxicity among ELBW infants. Our data conf...