Serum theophylline levels in asthmatic children after oral administration of two slow-release theophylline preparations.

Serum theophylline levels were measured throughout the day in 65 asthmatic children receiving one of two slow-release theophylline compounds. There was a wide interindividual variation in levels obtained with similar doses of pure theophylline, and also a wide intraindividaual variation in levels throughout the day, suggesting that the rates of release and/or absorption of theophylline from these compounds are not uniform. There were fewer side effects associated with taking these compounds than with choline theophyllinate.