title: Changes in the steady-state pharmacokinetics of theophylline during treatment with dirithromycin.
abstract: The steady-state plasma concentrations and pharmacokinetic characteristics of theophylline were studied during intermittent treatment with dirithromycin. The addition of dirithromycin (500 mg orally once daily at 7:00 AM) to a sustained-release theophylline dosing regimen (200 mg every 12 hours) elicited small changes in the steady-state pharmacokinetics of theophylline. Mean steady-state plasma theophylline trough concentrations (Cmin) were invariant before, during, and after dirithromycin treatment; however, mean average steady-state plasma theophylline concentrations (Cav) declined by 18% during dirithromycin treatment (P less than .05), and mean peak plasma concentrations (Css,max) declined by 26% (P less than .01). Theophylline clearance (CL/F) exhibited an increase of comparable magnitude during dirithromycin treatment, although the increase in CL/F was not statistically significant (.05 less than P less than .1). Dirithromycin treatment alters the steady-state pharmacokinetics of theophylline; however, the magnitude of the changes is small and is not likely to modify treatment outcomes.
authors.affiliation: Department of Pharmacology, University of Toledo College of Pharmacy, OH 43606.
authors.forename: K
authors.initials: K
authors.lastname: Bachmann
authors.forename: M
authors.initials: M
authors.lastname: Nunlee
authors.forename: M
authors.initials: M
authors.lastname: Martin
authors.forename: T
authors.initials: T
authors.lastname: Sullivan
authors.forename: L
authors.initials: L
authors.lastname: Jauregui
authors.forename: K
authors.initials: K
authors.lastname: DeSante
authors.forename: G D
authors.initials: GD
authors.lastname: Sides
mesh_terms: D000284:Administration, Oral; D000328:Adult; D000900:Anti-Bacterial Agents; D003692:Delayed-Action Preparations; D004347:Drug Interactions; D004917:Erythromycin / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000097:blood / Q000494:pharmacology; D006706:Homeostasis; D006801:Humans; D018942:Macrolides; D008297:Male; D013806:Theophylline / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*; D013997:Time Factors
chemical_list: D000900:Anti-Bacterial Agents; D003692:Delayed-Action Preparations; D018942:Macrolides; C053853:dirithromycin; D004917:Erythromycin; D013806:Theophylline