title: Cefotaxime and desacetylcefotaxime pharmacokinetics in very low birth weight neonates.
abstract: The single-dose pharmacokinetics of cefotaxime (CTX) and desacetylcefotaxime (dCTX) after a 50.0 mg/kg intravenous dose were evaluated in 18 very low birth weight neonates (13 male; 1015.6 +/- 349.8 gm; 28.4 +/- 2.4 weeks gestational age) during the first week of life. Microanalytic high-performance liquid chromatography was used to quantitate both CTX and dCTX from serum. A two-compartment open model best characterized the disposition of CTX during a 24-hour post-dose period. The disposition of dCTX was adequately characterized by a one-compartment model. The elimination half-life, apparent steady-state volume of distribution, and total body clearance of CTX (mean +/- SEM) were 4.44 hours, 0.461 +/- 0.027 L/kg, and 0.074 +/- 0.003 L/hr/kg, respectively. Peak concentrations (mean +/- SD) of dCTX (17.96 +/- 5.54 mg/L) occurred at 0.6 to 8.3 hours (5.9 +/- 1.9 hours) after CTX administration, and the apparent elimination half-life of dCTX was 9.36 hours. Comparison of CTX and dCTX pharmacokinetic parameters between very low birth weight neonates who weighed less than 1000 gm (n = 9; 703.3 +/- 46.6 gm; 27.0 +/- 0.8 weeks gestational age) and greater than or equal to 1000 gm (n = 9; 1328.8 +/- 48.6 gm; 29.8 +/- 0.5 weeks gestational age) revealed no significant differences, but significant linear correlations were found between gestational age and weight versus CTX half-life and total body clearance. Because of the prolonged clearance of both CTX and dCTX in the very low birth weight neonate, a CTX dose of 50 mg/kg every 24 hours may provide effective serum concentrations for susceptible infections outside the central nervous system.
authors.affiliation: Department of Pediatrics, University of Arkansas for Medical Sciences, Little Rock.
authors.forename: G L
authors.initials: GL
authors.lastname: Kearns
authors.forename: R F
authors.initials: RF
authors.lastname: Jacobs
authors.forename: B R
authors.initials: BR
authors.lastname: Thomas
authors.forename: T L
authors.initials: TL
authors.lastname: Darville
authors.forename: J M
authors.initials: JM
authors.lastname: Trang
mesh_terms: D002439:Cefotaxime / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000097:blood / Q000493:pharmacokinetics*; D002851:Chromatography, High Pressure Liquid; D005260:Female; D006801:Humans; D007230:Infant, Low Birth Weight / Q000097:blood / Q000378:metabolism*; D007231:Infant, Newborn; D007234:Infant, Premature / Q000097:blood / Q000378:metabolism*; D008297:Male
chemical_list: C029281:desacetylcefotaxime; D002439:Cefotaxime