Comparison of serum theophylline levels in asthmatic children receiving sustained-release and rapid-release theophylline tablets.

Serum theophylline levels were compared after the administration of a sustained-release (Theo-Dur, Key Pharmaceuticals, USA) vs. a rapid-release (Glyphyllin, Ikapharm, Israel) theophylline preparation to 24 children suffering from chronic bronchial asthma. They received each of the two drugs for a 5-d period, and serum theophylline levels were determined on the 6th d. Therapeutic serum levels were achieved in 66.6 and 75% of the patients receiving sustained-release and rapid-release theophylline preparations, respectively. The peak-trough difference for the rapid-release drug was higher than that of the sustained-release preparations (5.5 +/- 2.6 micrograms/ml vs. 2.6 +/- 2.3 micrograms/ml). Both drugs caused nearly the same low percentage of side effects (15 and 16.6%). A noncompliance rate of 16.6% was found with the rapid-release drug, and all the parents preferred the sustained-release drug is preferable for chronic treatment of children with bronchial asthma, as it maintains more stable serum theophylline levels and has a higher compliance rate.