title: Renal clearance of theophylline and its major metabolites: age and urine flow dependency in paediatric patients.
abstract: The renal clearance of theophylline (TH) and its metabolites 1,3-dimethyluric acid (1,3-DMU), 3-methylxanthine (3-MX), and 1-methyluric acid (1-MU) has been studied in 10 children aged 8 months to 14 years. Individual renal clearances were calculated from serum levels and amounts excreted in urine after i.v. administration of the parent drug. The clearance of 1,3-DMU was found to depend both upon urine flow rate and age, which are interrelated. An effect of urinary pH was expected, but was not studied. Consistent age-dependent changes in the relative quantities of metabolites excreted were not observed.
authors.affiliation: Pharmazeutisches Institut, Pharmazeutische Technologie, Rheinischen Friedrich-Wilhelms-Universität, Bonn, Federal Republic of Germany.
authors.forename: I
authors.initials: I
authors.lastname: Bonnacker
authors.forename: D
authors.initials: D
authors.lastname: Berdel
authors.forename: R
authors.initials: R
authors.lastname: Süverkrüp
authors.forename: A
authors.initials: A
authors.lastname: von Berg
mesh_terms: D000293:Adolescent; D000375:Aging / Q000378:metabolism; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D007275:Injections, Intravenous; D008297:Male; D013806:Theophylline / Q000652:urine*; D014527:Uric Acid / Q000031:analogs & derivatives / Q000652:urine; D014563:Urodynamics; D014970:Xanthines / Q000652:urine
chemical_list: D014970:Xanthines; D014527:Uric Acid; C030530:1-methyluric acid; D013806:Theophylline; C031274:1,3-dimethyluric acid; C029703:3-methylxanthine