Influence of food on steady state serum concentrations of theophylline from two controlled-release preparations.

The influence of food on the bioavailability of the controlled-release theophylline preparations Theostat and Theolair was studied in 12 healthy subjects after multiple dosing (b.i.d. for 6 days). On the morning of days 5 and 6, the volunteers took these products once after overnight fasting and once after a high-fat breakfast. For Theostat, serum theophylline levels and pharmacokinetic parameters were not affected by the intake of breakfast. For Theolair, serum theophylline concentrations were markedly lower after breakfast, with a significant decrease of Cmax and AUC. This study confirms the necessity of studying the influence of food on the bioavailability of theophylline controlled-release preparations.