Improvements in impulse oscillometry after chronic dosing with formoterol compared with salmeterol might reflect better deposition to small airways

Effects of small-particle long-acting beta-agonists on the small airways have been poorly documented. This study used impulse oscillometry (IOS) to compare single and repeated dosing effects of small- (formoterol MDI) and large-particle (salmeterol DPI) long-acting beta-agonists.

16 patients received either formoterol or salmeterol twice daily plus inhaled corticosteroid for 1 to 2 weeks with a 1- to 2-week washout period in between (mean age, 43 years; FEV1, 80%, FEF25-75, 48%).

There were greater improvements with formoterol versus salmeterol in all IOS outcomes but not FEV1.

Significant improvements in IOS outcomes but not spirometry results occurred after chronic dosing with formoterol compared with salmeterol. This might reflect better deposition to the entire lung, including the small airways.

References:

Effects of formoterol or salmeterol on impulse oscillometry in patients with persistent asthma. Arvind Manoharan et al. JACI, March 2016, Volume 137, Issue 3, Pages 727–733.e1.
http://www.jacionline.org/article/S0091-6749(15)00861-1/abstract

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