Beta2-agonists for acute bronchitis

The optimal treatment for acute bronchitis is not clear. Because many patients with acute bronchitis have airflow limitation as well as cough, beta2-agonists may be useful.

To determine whether beta2-agonists improve the symptoms of acute bronchitis in patients who do not have underlying pulmonary disease.

Cochrane Library, MEDLINE, EMBASE, and Conference Proceedings using "bronchodilator (exp)", "adrenergic beta-agonist (exp)", or "sympathomimetics (exp)" and "bronchitis" or "cough"; Science Citation Index for referenced publications; and letters to manufacturers of beta2-agonists.

Trials in which patients (adults or children age > 2 years) without known pulmonary disease who were diagnosed with acute bronchitis or acute cough without other cause were randomized to beta2-agonist vs. placebo, no treatment, or alternative treatment.

Three reviewers independently first selected outcomes and evaluated trial quality while blinded to study results, and then extracted data. Trials in children and in adults were analyzed separately.

Two trials in children with acute cough and no evidence of airway obstruction did not find any benefits from beta2-agonists. Five trials in adults with acute cough or acute bronchitis had mixed results, but overall summary statistics did not reveal any significant benefits from beta2-agonists. Subgroups of patients with evidence of airflow limitation had lower symptom scores if given beta2-agonists in one trial; and the trials that did note quicker resolution of cough in patients given beta2-agonists were those that had a higher proportion of patients with wheezing at baseline. Patients given beta2-agonists (whether oral or inhaled) were more likely to report tremor, shakiness, or nervousness than patients in the control groups (NNH for children 9, 95% CI 5 to 100; NNH for adults 2.3, 95% CI 2 to 3).

There is no evidence to support using beta2-agonists in children with acute cough who do not have evidence of airflow obstruction. There is also little evidence that the routine use of beta2-agonists for adults with acute cough is helpful. These agents may reduce symptoms, including cough, in patients with evidence of airflow obstruction; but this potential benefit is not well-supported by the available data and must be weighed against the adverse effects associated with beta2-agonists.