Food-induced changes in the absorption of Theostat 300®, a controlled release formulation of theophylline, have been studied in healthy volunteers. This open, randomised, 3-way, single-dose study involved 12 volunteers who received the drug either while fasting, or with a standardised low-fat (10g), or high-fat (60g) breakfast. Each subject was studied over a 3-week period, with 3 separate days of oral treatment and a 7-day washout period between treatments.The results showed no differences in AUC0-24and tmaxvalues between the 3 kinds of diet. The only differences observed concerned absorption. Food intake increased Cmaxvalues by 20%. The steady-state peak concentration obtained by means of simulated plasma levels was not influenced by food intake. This slight food-drug interaction of Theostat 300® seemed to be of no clinical significance.