The effect of steroids on theophylline absorption.

The effect of hydrocortisone on plasma theophylline concentrations was evaluated in 20 patients suffering from chronic bronchitis or stable bronchial asthma. Choline theophyllinate (400 mg) was orally administered every 12 h for 8 days and blood samples were taken every 2 h during the day for the measurement of theophylline concentrations. Intravenous bolus injections of 500 or 1000 mg hydrocortisone on day 5 or day 7, respectively, did not significantly alter plasma theophylline concentrations.