Single-dose comparison of formoterol (Oxis) Turbuhaler 6 microg and formoterol Aerolizer 12 microg in moderate to severe asthma: a randomised, crossover study.

Formoterol inhaled via Turbuhaler (Oxis) or Aerolizer (Foradil) produces fast and long-lasting bronchodilation in asthmatic patients. While formoterol Turbuhaler provides sustained efficacy for > or =12h at a metered dose of 6 microg (delivered dose 4.5 microg), the recommended metered dose for formoterol Aerolizer is 12 microg (delivered dose unknown). This difference may be attributable to improved lung deposition with the Turbuhaler. This open, randomised, crossover study compared the effects of a single metered dose of formoterol Turbuhaler 6 microg and formoterol Aerolizer 12 microg in 16 patients with stable moderate-to-severe asthma. Pulmonary function, assessed by measuring specific airway conductance (sGaw), was determined at intervals of < or =8h post-inhalation of each drug on separate study days. Both inhalers increased sGaw at all time points. There were no significant differences between the two formulations in onset of activity, maximum effect, duration of effect or area under the response curve. Furthermore, both treatments were well tolerated with no differences in adverse events, blood pressure or heart rate; thus the formoterol Turbuhaler may, therefore, have an improved therapeutic index. This pilot study indicates that the same clinical effect can be achieved with half the metered dose (6 microg) of formoterol Turbuhaler compared with formoterol Aerolizer (12 microg).