Combined anticholinergic therapy in the management of acute asthma

In a hospital setting, first-line drugs for treatment of acute severe asthma are usually nebulized short-acting beta 2-agonists and systemic corticosteroids. Combining a nebulized beta 2-agonist with the anticholinergic agent ipratropium bromide may produce better bronchodilation than either drug alone, particularly in patients with more severe episodes. A recent study from New Zealand compared nebulized beta 2-agonist alone or in combination in patients presenting with acute severe asthma to the emergency department. Combined treatment produced a significantly greater change in forced expiratory volume in 1 s (FEV1) than salbutamol alone. Factors predicting a poor bronchodilator response (irrespective of study drug received) were frequent use of inhaled beta 2-agonist before presenting at the emergency department, increased severity and duration of attack and older age. Patients presenting with more severe asthma had taken more inhaled bronchodilator before presentation and were therefore likely to be higher on the dose-response curve and thus less likely to derive benefit from additional bronchodilator therapy. The patients most likely to benefit from the addition of nebulized ipratropium bromide were those who had taken less inhaled beta 2-agonist in the previous 6 h. A combined analysis of three large studies on anticholinergic therapy, including the New Zealand study, has shown a 17% reduction in risk of subsequent admission (R = 0.83, 95% CI 0.63-1.1). Thus, nebulized ipratropium bromide imparts a small improvement in lung function when compared with salbutamol alone; however, further studies are needed to determine if multiple doses of combined anticholinergic/beta 2-agonist treatment reduce need for admission.