Comparative study on the clinical efficacy of theophylline variable serum concentrations therapy and round-the-clock therapy.

Depending on the administration method, highly effective therapeutic variable serum concentrations (VSC) of theophylline can be attained only in the time range of frequent asthma attacks. We used an oral sustained-release theophylline preparation in seven patients with bronchial asthma (two males and five females; mean age: 38.7 years) who had required more than two admissions per year due to bronchial asthma attacks, despite being treated with round-the-clock (RTC) therapy of theophylline and inhalation of steroids. We examined the annual frequency of admissions and the peak expiratory flow rate (PEFR) in remission. Even though no difference was noted in the serum concentrations of theophylline in the morning (the time range of attack) between RTC therapy and VSC therapy, the mean number of admissions during VSC therapy was 1.14, compared with 3.86 recorded during RTC therapy (p < 0.001). PEFR in remission showed a significant improvement with VSC therapy, compared with PEFR recorded during RTC therapy (p < 0.05). VSC therapy proved to be useful for patients who failed to attain favorable control of asthma attacks by RTC therapy.