Effects of inhaled beclomethasone dipropionate on beta 2-receptor function in the airways and adrenal responsiveness in bronchial asthma.

Sixteen patients suffering from bronchial asthma, with or without chronic bronchitis, sufficiently severe to be treated with inhaled corticosteroids, were studied in a single-blind trial (blind observer) of beclomethasone dipropionate (BDP) given in three randomized dosage regimens: 500, 1000 and 2000 micrograms per day, each for 4 weeks. The beta 2-adrenergic agonist response curve showed a dose-dependent increase in FEV1 which was not affected by different doses of BDP. A small but significant reduction in basal cortisol levels was observed after BDP 500 micrograms/day. There was no significant difference between the various doses of BDP in reducing cortisol level and stimulation with tetracosactide remained unchanged. The study showed a gradual, dose-dependent improvement in lung function, statistically significant for morning peak expiratory flow rate at BDP 2000 micrograms/day. Dyspnoea score and beta 2-agonist use decreased, reflecting the anti-asthmatic effects. An increase in total leukocyte count was observed, together with a decrease in the eosinophil count. Oral candidiasis was seen in 2 out of 16 patients. It is concluded that the clinical anti-asthmatic effects of corticosteroid treatment by inhalation are not due to modulation of beta 2-receptor function in the airways.