Controlled-release theophylline and proxyphylline in asthmatics: a comparative study.

In a short-term study, a new sustained-release preparation of proxyphylline (2400 mg/day) was compared to theophylline (800 mg/day) and placebo. A double-blind crossover design was used, and 10 adult asthmatics participated. No significant differences were found between the treatments with regard to relief of asthma symptoms, need for additional medication or incidence and intensity of side-effects. In the placebo period, morning peak-flow was significantly lower compared to active treatment periods.