[Effects of once-daily low-dose administration of sustained-release theophylline on airway inflammation and airway hyperresponsiveness in patients with asthma].

Bronchial asthma is eosinophilic airway inflammation with enhanced airway responsiveness induced by eosinophilic granule proteins such as eosinophilic cationic protein (ECP) that are released from eosinophils. In the present study using 30 outpatients with mild to moderate asthma who had no history of treatment with steroid inhalation, we examined the effects of 4-week low-dose (200 mg/day) treatment with Uniphyl Tablets, a sustained-release theophylline formulated for once-daily dosing, on airway inflammation and airway hyperresponsiveness, as well as on respiratory function. Uniphyl Tablets significantly (p < 0.01) decreased peripheral blood eosinophil count from 647.00 to 444.17/mm3 and ECP level (geometric mean) from 1318 to 741 ng/ml and improved airway hyperresponsiveness as indicated by a decrease in airway hyperresponsiveness (Dmin, geometric mean) from 1.15 to 6.70 units. FEV1.0 and PEF showed statistically significant (p < 0.01) improvement from 2.39 to 2.69 L and from 6.21 to 7.14 L/sec, respectively. V25 and V50 also showed statistically significant (p < 0.05) improvement. Mean blood theophylline concentration at the time the improvements were seen was 3.95 mg/mL. These results suggest that low-dose administration of Uniphyl Tablets has anti-airway inflammatory and anti-airway hyperresponsiveness effects in mild to moderate asthmatic patients.