FREE NEJM E-TOC    HOME   |   SUBSCRIBE   |   CURRENT ISSUE   |   PAST ISSUES   |   COLLECTIONS   |   Search Term  Advanced Search

Sign in | Get NEJM's E-Mail Table of Contents — Free | Subscribe

Previous Volume 295:413-416 August 19, 1976 Number 8 Next

	Add to Personal Archive Add to Citation Manager Notify a Friend E-mail When Cited PubMed Citation

Abstract

To characterize further the pharmacokinetics of theophylline in premature infants, its concentraion in blood was measured by high-pressure liquid chromatography after intravenous infusion given to six apneic premature newborns three to 15 days of age. Theophylline's apparent volume of distribution was 0.690 +/- 0.095 liters per kilogram (mean +/- S.E.), a value similar to that of children, but the half-life (30.2 +/- 6.5 hours) was nine times longer. Blood clearance rate (17.6 +/- 2.3 ml per kilogram per hour) was lower than plasma clearance rate (100 ml per kilogram per hour) of young children. At a total plasma concentration of 17 mg per liter, 56.4 +/- 3.8 and 36.4 +/- 3.8 per cent of the theophylline was bound to adult or full-term cord plasma proteins, respectively. Bilirubin and theophylline did not compete for plasma protein. Calculations suggest that a loading doses of 5.5 mg per kilogram and a maintenance dose rate of 1.1 mg per kilogram per eight hours would achieve and maintain a mean blood concentration of 8 mg per liter (about 10 mg per liter in plasma).

This article has been cited by other articles:

• Aranda, J., Louridas, A., Vitullo, B., Thom, P, Aldridge, A, Haber, R (1979). Metabolism of theophylline to caffeine in human fetal liver. Science 206: 1319-1321 [Abstract]