Once-daily inhaled corticosteroids in mild to moderate asthma: improving acceptance of treatment.

Despite the established efficacy of inhaled corticosteroids in improving lung function in asthma, there has not been a corresponding improvement in morbidity and mortality associated with the disease, which, in part, may result from non-compliance with the prescribed regimen. The reasons for this are many and varied, but an important measure in improving the level of compliance in asthma patients is simplification of the treatment regimen, which may be achieved by reducing the dose frequency and improving the ease of administration. In clinical trials designed to determine whether a reduction in dose frequency to once daily is associated with similar efficacy to that with more frequent administration, a number of studies have shown that once-daily administration of inhaled corticosteroids in both adults and children is as effective in controlling asthma as twice-daily administration of the same dosage, both when given as initial therapy in corticosteroid-naïve patients and in patients already receiving an inhaled corticosteroid. The drug for which most evidence to support a dosage change from twice-daily to once-daily therapy currently exists is budesonide, though limited evidence with other inhaled corticosteroids such as beclomethasone dipropionate, fluticasone propionate and flunisolide also supports once-daily use. Despite the larger single dosage with once-daily budesonide therapy, there has been no evidence in clinical trials of a greater incidence of local adverse effects such as hoarseness, throat irritation or oropharyngeal candidosis, and no evidence of adrenal suppression or growth retardation. Since compliance is an important factor that can affect the success or failure of asthma therapy, a reduction in the frequency of administration to once daily offers the potential advantage of improved compliance with treatment and hence better control of asthma. In the short term clinical trials conducted to date, patient preferences have favoured the once-daily regimen over twice-daily administration. When combined with other (e.g. educational) measures to improve patient compliance, a switch from twice-daily (or more frequent) administration to once-daily inhaled corticosteroid therapy seems likely to be beneficial in improving the long term outcome of treatment.