Slow release theophylline in patients with airways obstruction with particular reference to the effects of food upon serum levels.

Eighteen patients with airways obstruction were given slow release theophylline and were then investigated to determine the influence of a standard meal upon the serum levels achieved over the ensuing 12-hour period. After food the peak to trough differences were decreased and the serum levels were significantly lower over the first 6 hours. In this study, the patients were given 10 mg/kg/day of slow release theophylline and none subsequently was found to have toxic levels, therefore this was considered to be a reasonable dose with which to initiate therapy in adults with uncomplicated airflow limitation. However even under the strictly controlled conditions of the study there were wide variations between individuals in the blood levels achieved and serum monitoring is necessary to use theophylline in an optimal fashion.