Pharmacology of trimethoprim-sulfamethoxazole in newborn infants

J Pediatr. 1982 Apr;100(4):647-50. doi: 10.1016/s0022-3476(82)80778-6.


The pharmacokinetic parameters of sulfamethoxazole and trimethoprim were measured in 12 newborn infants of less than 3 days postnatal age, following a single or repeated intravenous injection. The mean half-lives for SMZ and TMP were 16.5 hours and 19.0 hours, respectively. The mean volumes of distribution were SMZ 0.48 L/kg and TMP 2.7 L/kg. The mean drug clearances were SMZ 0.65 ml/minute and TMP 3.31 ml/minute. From these data the recommended loading dose is SMZ 10 mg/kg with TMP 3 mg/kg, and the maintenance dose is SMZ 3 mg/kg with TMP 1 mg/kg twice daily. No adverse side effects were seen during treatment, and the bilirubin-binding capacity of albumin were not changed at therapeutic concentrations of the antimicrobial drugs.

MeSH terms

  • Drug Therapy, Combination
  • Half-Life
  • Humans
  • Infant, Newborn
  • Infant, Newborn, Diseases / drug therapy*
  • Injections, Intravenous
  • Kinetics
  • Klebsiella Infections / drug therapy*
  • Metabolic Clearance Rate
  • Sulfamethoxazole / administration & dosage
  • Sulfamethoxazole / blood*
  • Trimethoprim / administration & dosage
  • Trimethoprim / blood*


  • Trimethoprim
  • Sulfamethoxazole