Changes in the steady-state pharmacokinetics of theophylline during treatment with dirithromycin.
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.
Bachmann
K
K
Department of Pharmacology, University of Toledo College of Pharmacy, OH 43606.
Nunlee
M
M
Martin
M
M
Sullivan
T
T
Jauregui
L
L
DeSante
K
K
Sides
G D
GD
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
D000900:Anti-Bacterial Agents; D003692:Delayed-Action Preparations; D018942:Macrolides; C053853:dirithromycin; D004917:Erythromycin; D013806:Theophylline