Efficacy of sustained release theophylline given at three different evening intake times in addition to a baseline medication.
In this randomized crossover study of 26 outpatients with bronchial asthma the efficacy of a new once-daily theophylline formulation given in addition to a baseline medication was investigated; moreover, under steady state conditions, the effect of three evening intake times (6, 8 and 10 p.m.) on 24 h pharmacokinetics and peak-expiratory flow profiles was evaluated. The theophylline dose had been individually titrated. The pharmacodynamic results show a marked improvement of 24 h peak expiratory flow values after adding theophylline to a drug therapy including inhalative beta 2-agonists and corticosteroids in nearly all and inhalative anticholinergics in 50% of the treated outpatients. No significant differences between the pharmacokinetic characteristics and the 24 hr averages (mesors) of peak expiratory flow at the three different intake times 6, 8 and 10 p.m. were found; however, intake at 10 p.m. resulted in the highest nocturnal excess of serum theophylline concentrations and the highest peak expiratory flow during the early morning hours between 2 and 6 a.m.