Absorption of oral neomycin in premature infants with suspected necrotizing enterocolitis

The oral absorption of neomycin was studied in 2 premature infants (32 weeks of gestation) with suspected necrotizing enterocolitis. 1 infant received 50 mg and the other 100 mg of neomycin sulfate/kg/day in 4 divided doses for approximately 7 days. Plasma neomycin levels were determined by a micro, sensitive and specific high-performance liquid chromatographic assay developed in our laboratory. Plasma levels as high as 2.9 and 4.5 micrograms/ml were observed in these 2 infants. A urinary recovery study for 1 infant revealed that at least 3.7% of the oral dose was absorbed. The significant and persistent plasma levels of neomycin in these patients suggest the need for extreme caution in using this potentially toxic antibiotic for prolonged treatment in neonates.