Pharmacokinetics of oral and intravenous indomethacin in preterm infants.

The pharmacokinetic profile of indomethacin administered either orally or intravenously in 13 preterm infants with significant patent ductus arteriosus (PDA) is reported. 9 infants received oral indomethacin and 4 received intravenous therapy. Plasma half-life was significantly prolonged as compared to adult values and demonstrated significant correlation with gestational age. Mean half-life in neonates less than 32 weeks gestation was 17.2 (0.8) vs. 12.5 (0.5) h for neonates greater than 32 weeks gestation. Bioavailability of the oral dosage based on AUC was 13% but no difference was observed in the plasma protein binding or distribution volume of drug as compared to adult values. No serious complications could be attributed to the use of indomethacin at these dose levels in the premature infant.