Formoterol used as needed in patients with intermittent or mild persistent asthma.

Objective: To study the effectiveness and safety of as-needed treatment of formoterol compared with the short-acting alternative terbutaline.

Methods: Two double-blind, 12-month, parallel-group, non-inferiority trials comparing as-needed use of formoterol (Oxis) 4.5 microg and terbutaline (Bricanyl) 0.5 mg via dry-powder inhaler (Turbuhaler), one in 675 patients with intermittent and one in 455 patients with mild persistent asthma, overall 6-87 years of age. Peak expiratory flow (PEF), symptoms, rescue medication use, exacerbations, airway responsiveness (metacholine challenge; subgroup of 127 patients), systemic effects (high single-dose test; subgroup of 87 patients), and safety (adverse events) were assessed.

Results: Formoterol 4.5 microg was as effective as terbutaline 0.5 mg with regard to morning PEF (non-inferiority; lower 95% confidence interval limit above -10 L/min). Metacholine sensitivity, exacerbation rates or use of rescue medication did not differ between treatments. Formoterol 54 microg was shown to give less systemic effects than terbutaline 6 mg. Both treatments were safe and well tolerated.

Conclusions: Formoterol 4.5 microg used as needed was at least as effective and safe as terbutaline 0.5 mg used as needed in intermittent and mild persistent asthma, and was associated with less systemic effects when administered as high single doses.