Is a uniform round-the-clock theophylline blood level necessary for optimal asthma therapy in the adolescent patient?

Twenty-one patients, 12 to 18 years of age, with nocturnal asthma controlled with sustained-release theophylline administered twice daily, were enrolled in a 10-week, double-blind, two-way crossover study that compared Theo-Dur tablets administered twice daily with an equivalent daily dose of Uniphyl tablets administered once daily at bedtime. Seventeen patients completed the study. The mean morning theophylline serum level obtained with Uniphyl tablets was significantly higher than that obtained with Theo-Dur tablets (13.1 versus 9.6 micrograms/ml, p = 0.02). The mean evening serum level was significantly lower with Uniphyl tablets (6.3 versus 10.1 micrograms/ml, p = 0.003). Despite these differences in serum concentrations, morning and evening pulmonary function test values (forced expiratory volume in one second and peak expiratory flow rate) and symptom scores were nearly identical for the two preparations, as was the supplemental use of aerosol bronchodilators. Once-daily dosing with Uniphyl tablets may benefit adolescent patients with nocturnal asthma by increasing compliance and providing better asthma control. In addition, the lower daytime theophylline levels produced by this preparation may also reduce long-term adverse effects on behavior and cognition.