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[Posture and circadian variations in serum theophylline concentrations]
M Kishida1, K Hukushima, Y Iikura
1Department of Pediatrics, Tottori University, School of Medicine.
Arerugi = [Allergy]
|October 1, 1990
Summary
Posture significantly impacts theophylline absorption. Standing increases the rate of absorption (ka) compared to lying down, explaining circadian variations in theophylline levels.
Area of Science:
- Pharmacokinetics
- Chronopharmacology
- Drug Absorption
Context:
- Circadian variations in theophylline pharmacokinetics are known, with faster morning absorption rates (ka) observed for immediate-release aminophylline tablets compared to evening doses.
- Previous research indicated altered absorption kinetics without significant changes in other pharmacokinetic parameters like AUC, Vd, kel, or t1/2.
Purpose:
- To investigate the effect of posture on theophylline absorption in pediatric asthma patients.
- To determine if posture differences can explain the observed diurnal variations in theophylline absorption rates.
Summary:
- Seven asthmatic children received immediate-release aminophylline tablets in the morning, tested under both standing and lying conditions.
- Serum theophylline concentrations were monitored for 5 hours post-dose.
- Higher mean theophylline levels and a significantly faster absorption rate (ka) were observed in the standing position, with no significant changes in other pharmacokinetic parameters.
Impact:
- Posture is identified as a key factor influencing theophylline absorption rate (ka).
- The findings suggest that postural differences, specifically standing versus lying, may be the primary cause of slower evening theophylline absorption, contributing to diurnal variations.
- This research provides crucial insights for optimizing theophylline dosing strategies in asthma management.