The aim of this study was to demonstrate the equivalent efficacy of inhaled formoterol in asthmatic patients, either given as-needed or on a regular twice-daily schedule.

Randomised, open 12-week study in patients with mild to moderate asthma not adequately controlled with inhaled glucocorticosteroids alone. Patients received inhaled formoterol as needed or on a regular schedule (2×2 puffs/day with 6μg formoterol per puff). Patients in the twice-daily formoterol group could use salbutamol as a rescue medication. The primary endpoint was the number of patients with asthma exacerbations in each group.

Thirty-nine centres randomised 359 patients. The number of patients with asthma exacerbations showed neither a clinically relevant nor a statistically significant difference between groups: formoterol as-needed: 3.95% (7 of 177); twice daily: 3.45% (6 of 174). Patients in the formoterol as-needed group used significantly less formoterol (−1.5 puffs per day; P<0.0001). Including the saved rescue medication (up to one puff per day), total beta-2 agonist use in the formoterol as-needed group decreased by approximately 2–2.5 puffs per day.

Both formoterol treatment schedules were well tolerated. Musculoskeletal pain and tremor were less frequent in the formoterol as-needed group: headaches were slightly more frequent.

Formoterol given as needed and without additional beta-2 agonist, and formoterol given on a regular basis twice daily, supplemented by salbutamol as a rescue medication, appeared equally effective in this clinical study. Drug consumption was markedly lower in the former group.