[The anti-inflammatory action of an oral sustained-release theophylline preparation. Results of a clinical pilot study with low dosages].

A pilot study in 14 patients with mild asthma was performed to study the anti-inflammatory efficacy of theophylline (CAS 58-55-9). At the start, during and at the end of a 3 months' treatment with oral sustained release theophylline and during 1 week thereafter, the influence on airway hyperreactivity and ECP (eosinophil cationic protein) serum levels was investigated. Airway responsiveness was expressed as the cumulative provocative dose of methacholine necessary to decrease FEV1 by 20% (PD20-FEV1). Data of 8 patients were suitable for evaluation. At a mean predose serum concentration of 6.5 mg/l, theophylline increased the mean PD20-FEV1 for methacholine from 151 micrograms (at start) to 332 micrograms (at the end of medication), and reduced the mean ECP serum concentration from 34.6 to 24.5 micrograms/l. Up to 1 week after theophylline treatment, the improvement of airway hyperreactivity compared to the baseline was maintained, whereas ECP-serum levels tended to increase. Thus, theophylline markedly attenuated airway hyperreactivity in patients with bronchial asthma at "subtherapeutic" serum theophylline concentrations as well as ECP serum concentrations, suggesting the anti-inflammatory efficacy of theophylline. These observations may have therapeutic implications in the treatment of patients with mild asthma. A slight improvement of lung function and dyspnoea, and a reduction of additional beta 2-bronchodilator use was also observed. Two patients only complained of slight nausea, tremor and restlessness.