Are inhaled beta agonists effective for the treatment of chronic, nonspecific cough in children?
The single clinical trial on this topic found that inhaled beta agonists do not reduce cough frequency or improve symptoms in children with chronic, nonspecific cough.
Cough lasting more than three weeks in children often is caused by asthma, postnasal drip, gastroesophageal reflux disease, or chronic exposure to irritants such as tobacco smoke or allergens; it also may be attributed to overestimation of symptoms by parents. Rarely, it is caused by a serious problem such as cystic fibrosis or tuberculosis. When these causes have been excluded, chronic, nonspecific cough, sometimes called “cough variant asthma,” often is diagnosed.
The authors of this systematic review identified only one study that compared an inhaled beta agonist with placebo in a randomized, double-blind trial. This study compared inhaled albuterol (Proventil) in a dosage of 200 mcg twice daily via metered dose inhaler with placebo in 42 children who had chronic, nonspecific cough.1 At the end of the one-week study, the researchers found no differences between groups regarding cough frequency, symptom score, airway responsiveness, or sensitivity of cough receptors to capsaicin. The study was small, and although it was powered to detect a 70 percent difference in cough frequency between groups, it might have missed a small but clinically significant benefit with inhaled beta agonists. The authors note that observational studies and examination of the symptoms of children in placebo groups suggest that cough tends to improve over time.
Another Cochrane review2 performed in 2005 by the same group of researchers found a possible benefit from high-dose inhaled corticosteroids in two studies with a total of 123 children; however, children in the placebo group also improved, and the clinical impact was of uncertain significance. An evidence-based guideline from the Finnish Medical Society3 recommends that treatment with inhaled corticosteroids be considered in children with cough-predominant asthma if pulmonary function testing is abnormal. For younger children who cannot cooperate adequately with pulmonary function testing, an empiric trial of inhaled corticosteroids should be considered.