Glucocorticoids and asthma. Studies of resistance and systemic effects of glucocorticoids.

Glucocorticoid resistance in asthma is genetically determined in a few individuals. Preliminary data are presented from a study showing interaction with a drug as another explanation for glucocorticoid resistance. In 6 healthy individuals, prednisolone concentrations were measured during 9 h after oral intake of 15 mg before and after 10 days' intake of 450 mg of rifampicin daily. An increased clearance of prednisolone was demonstrated. Systemic effects of inhaled glucocorticoids have also been studied. Comparison in healthy individuals between beclomethasone dipropionate given as a spray and as powder showed similar systemic effects with the two modes of administration. A new glucocorticoid for inhalation therapy, budesonide, was shown to have a weaker systemic effect than beclomethasone dipropionate. By rinsing the mouth with water after inhalation, it was possible to reduce the amount of drug swallowed, and our data showed a tendency towards less systemic effects after mouth-rinsing.