Current role of anticholinergic drugs in the treatment of asthma: key messages for clinical practice.

Anticholinergic bronchodilators such as tiotropium, a potent long-acting drug, are central to the symptomatic treatment of chronic obstructive pulmonary disease. Its role in asthma treatment has been recently investigated. This review critically evaluates documented evidence of clinical trials and assesses the therapeutic implications of anticholinergic drugs in asthma management. So far, the results of 10 Phases II and III randomized controlled trials evaluating the effect of adding tiotropium to the treatment of mild-to-moderate or severe asthma have been published. These trials had a duration of 4 to 52 weeks and involved 3368 subjects with mild-to-moderate asthma and 1019 subjects with severe asthma [corrected]. Also, 1 systematic review and 6 meta-analyses have appraised the results of published and unpublished trials investigating the role of tiotropium in asthma. The results of the trials in mild to moderate asthma showed that adding tiotropium to inhaled corticosteroids (ICSs) was not inferior to adding long-acting β2-agonists (LABAs). In addition, the safety and efficacy of tiotropium were similar to those of salmeterol. The results of studies on severe asthma showed that adding tiotropium to a treatment with high doses of an ICS plus LABA results in further improvement in lung function, increases the time to the first severe exacerbation of asthma and to worsening of asthma, and improves asthma control. Except for dry mouth, the safety profile of tiotropium was similar to placebo both in moderate and in severe asthma. Adding tiotropium to an ICS or ICS plus LABA improves lung function, symptoms, and asthma control, and in severe asthma, it increases the time to exacerbations, with good safety profile. The effect seems independent of baseline characteristics such as age, level of bronchial obstruction, smoking status, allergic status, and bronchial reversibility.