Comparison of once-a-day and twice-a-day theophylline in asthma

Sustained-release theophylline compounds given once (Uniphyl) or twice (Theodur) daily were compared in adult asthmatics. Following a single dose of oral medication, large and peripheral airways bronchodilation occurred; response to theophylline correlated significantly with the log plasma theophylline concentration. Cardiac output and stroke volume, measured noninvasively using the acetylene technique, also increased significantly. During maintenance therapy, both preparations caused similar improvements in pulmonary function and symptoms; however, side effects were less with once-daily therapy.