Adults with asthma who need more than standard inhaled-glucocorticoid therapy may benefit from add-on tiotropium (Spiriva), a long-acting anticholinergic agent, suggests an NIH-funded study of about 200 patients in the New England Journal of Medicine. Tiotropium is currently FDA approved to treat chronic obstructive pulmonary disease.

In the double-blind, placebo-controlled, crossover study, 14 weeks of add-on tiotropium was superior to double-dose glucocorticoid therapy and was noninferior to add-on salmeterol (Serevent, a long-acting beta-agonist) in terms of morning peak expiratory flow and several secondary outcomes, such as number of asthma-control days.

An editorialist welcomes this alternative to long-acting beta-agonists, which have been linked to rare but life-threatening asthma exacerbations. However, he notes that the long-term effectiveness of tiotropium compared with beta-agonists remains unknown, as does its potential for masking underlying airway inflammation.