Sustained release theophylline in nocturnal asthma.

Twice daily sustained release theophylline gave satisfactory steady serum theophylline concentrations in asthmatic children aged 7 to 14 years. The children showed improvement in symptoms, less frequent waking at night, reduced use of beta agonist inhalers, and improved early morning peak flows while being treated with this preparation. There was no improvement in peak flow at other times, but the patients recorded increased use of beta agonists during the placebo period.