Objectives: This study was designed to compare the effects of a 6-month treatment with budesonide 100 microg bid (low dose) and 400 microg bid (standard reference dose) in controlling symptoms and lung function in a group of asthmatics with moderate asthma (baseline FEV(1) > or = 50% and < or = 90% of predicted values) previously treated with inhaled beclomethasone dipropionate (500 to 1,000 microg/d). Moreover, we investigated whether or not asthma exacerbations could be treated by a short-term increase in the daily dose of budesonide.

Methods: After a 2-week run-in period and 1-month treatment with a high dose of budesonide (800 microg bid), 213 patients with moderate asthma were assigned to randomized treatments. Daily treatment included budesonide (bid) plus an additional treatment in case of exacerbation (qid for 7 days). Treatments were as follows: budesonide 400 microg plus placebo (group 1); budesonide 100 microg plus budesonide 200 microg (group 2); and budesonide 100 microg plus placebo (group 3). Symptoms and a peak expiratory flow (PEF) diary were recorded and lung function was measured each month. An exacerbation was defined as a decrease in PEF > 30% below baseline values on 2 consecutive days.

Results: We found that that 1-month treatment with a high budesonide dose remarkably reduced all asthma symptoms. Moreover, symptoms were under control in all treatment groups throughout the study period. Similarly, lung function improved and remained stable, and no relevant differences between groups were observed. In each treatment group, the majority of patients had no exacerbations. In patients treated with the standard budesonide dose (group 1), the number of exacerbations and days with exacerbations were significantly lower than in group 3 (intention-to-treat analysis). Additionally, patients treated with low budesonide dose plus budesonide (group 2) experienced a significantly lower number of exacerbations and days with exacerbations compared to group 3 (per-protocol analysis).

Conclusions: This study demonstrates that when patients with moderate asthma had reached a stable clinical condition with a high dose of budesonide, a low dose of budesonide (200 microg/d) is as effective as the standard dose (800 microg/d) in the control of symptoms and lung function over a period of several months. Furthermore, results showed that the addition of inhaled budesonide (800 microg/d) at onset of an asthmatic exacerbation has a beneficial clinical effect.