Effect of theophylline on cortisol plasma concentrations in patients with chronic obstructive pulmonary disease

To further understand the therapeutic action of theophylline, we investigated, in a randomized double-blind crossover study, the effects of a 4-day treatment with two different dosage regimens of theophylline on the circadian rhythm of cortisol plasma concentrations in seven COPD patients. Both theophylline regimens resulted in plasma concentrations in the therapeutic range (more than 7.5 mg/l). No significant differences between placebo and the active trial periods in the circadian rhythm of cortisol secretion were found. These results suggest that cortisol secretion is not influenced by therapeutic plasma concentrations of theophylline.