A double-blind comparative trial between two sustained-release theophylline preparations with individual doses in asthmatic in-patients.

Twenty-one patients, suffering from bronchial asthma, with a moderate and clearly reversible airway obstruction, completed a double-blind cross-over trial of two theophylline sustained-release preparations, Theolair Retard (= Theolair S.R. = Nuelin S.R.) and Theolin Retard (= Theo-Dur). The serum theophylline concentration curves of Theolin Retard were significantly flatter than the curves of Theolair Retard, with less peak-trough variation. Pulmonary function in both treatment groups appeared to be the same. There were no differences in side effects, nor in asthma symptoms. However, patients complained significantly more of coughing during treatment with Theolin Retard. In two patients using antacids, the peak-trough variation with Theolair Retard was considerably larger than average. The favourable theophylline concentration profile of Theolin Retard is not reflected in pulmonary function, side effects or asthma symptoms. For this group of asthmatic hospitalized inpatients the practical differences between the two preparations are not distinctive.