Sustained-release theophylline therapy for chronic childhood asthma.

The efficacy of continuous, around-the-clock sustained-release (S-R) theophylline therapy, adjusted to approximate serum or plasma steady state theophylline concentrations (Tc) of 15 microgram/ml three hours following the last dose, was assessed in 18 children suffering from moderately severe chronic asthma. Two of the three formulations studied, Slo-Phyllin Gyrocaps and Theo-Dur, had excellent bioavailability and produced stable therapeutic Tc throughout an eight-hour dosing interval, using average doses of 8.7 +/- 0.5 and 8.4 +/- 0.6 (SE) mg/kg/dose, respectively. Pulmonary function responses paralleled Tc and were also stable throughout the dosing interval. Aerolate provided comparatively less stability, and higher doses (11.3 +/- 0.7 mg/kg) were necessary to produce therapeutic Tc. Toxicity was not evident when dosage was adjusted to avoid Tc exceeding 20 microgram/ml. S-R theophylline therapy, with the use of formulations of acceptable bioavailability, provides excellent control of chronic childhood asthma, offers the advantage of extended dosing intervals, and encourages improved patient cooperation in drug compliance.