Comparison of formoterol and terbutaline for as-needed treatment of asthma: a randomised trial

Background Asthma guidelines recommend that long-acting inhaled beta -agoni sts should be used as maintenance therapy for patients with asthma inadequa tely controlled on an inhaled corticosteroid. We studied the safety and eff icacy of the long acting beta -agonist formoterol compared with terbutaline , each taken as needed, in patients with moderate to severe asthma. Methods Patients were taking an inhaled corticosteroid (mean dose 870 mug d aily) and had a forced expiratory volume in 1 a (FEV1) of at least 50% pred icted (mean 74%). Those requiring an inhaled beta -agonist three to eight t imes a day during the study run-in period (362 of 621 who started) were ran domly assigned formoterol 4.5 mug or terbutaline 0.5 mg as needed by Turbuh aler in daily doses up to 54 mug and 6 mg, respectively, for 12 weeks in a double-blind, parallel-group study. Analyses were by intention to treat. Findings The 362 randomised patients (157 men, 205 women) had a mean age of 47 years. Patients taking formoterol had a longer time to their first seve re asthma exacerbation (relative-risk ratio 0.55 [95% CI 0.34-0 8.9]), took fewer inhalations of study drug, and had larger increases in FEV1 (5%) and morning and evening peak expiratory flow (mean difference in increase 11 L /min and 8 L/min) than those taking terbutaline. No safety issues were iden tified. Interpretation When taken as needed, formoterol 4.5 mug provided better ast hma control than terbutaline 0.5 mg in patients requiring moderate doses of relief medication despite inhaled corticosteroid treatment. Safety studies should be extended to a wider population of patients with asthma.