Pharmacokinetics of enprofylline administered intravenously and as a sustained-release tablet at steady state in children with asthma.
The pharmacokinetics of enprofylline (3-propylxanthine) were studied in 10 children with asthma (mean age 7.9 years), after enprofylline 1 mg/kg given intravenously and after enprofylline 7.5 +/- 1.3 mg/kg given as a sustained-release tablet after 8 days of oral dosing twice daily. The mean +/- SD enprofylline serum elimination half-life was 1.06 +/- 0.20 hours, considerably shorter than the half-life reported in adults. The mean steady-state volume of distribution was 0.55 +/- 0.05 L/kg. The mean clearance rate was 0.44 +/- 0.06 L/hr/kg. The mean enprofylline serum concentration at steady state was 1.7 +/- 0.5 mg/L. The mean peak to trough ratio was 3.02 +/- 1.31. On the first and ninth study days, 87% +/- 8% and 90% +/- 16%, respectively, of the dose of enprofylline was recovered as unchanged drug in the urine. Enprofylline has a short half-life in children, but the sustained-release formulation provides stable serum concentrations and satisfactory relief of asthma throughout the 12-hour dosing interval.
Watson
W T
WT
Department of Pediatrics and Child Health, Faculty of Medicine, University of Manitoba, Canada.
Simons
K J
KJ
Simons
F E
FE
D001249:Asthma / Q000188:drug therapy* / Q000378:metabolism; D002648:Child; D003692:Delayed-Action Preparations; D005260:Female; D006207:Half-Life; D006801:Humans; D007275:Injections, Intravenous; D008297:Male; D014970:Xanthines / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*
D003692:Delayed-Action Preparations; D014970:Xanthines; C034347:enprofylline