Formoterol, a new long-acting selectiveβ 2-agonist, decreases airway responsiveness in children with asthma

Abstract

We compared the protective effect and duration of action of inhaled formoterol with salbutamol and placebo in 16 asthmatic children in a double-blind, cross-over study. All had an FEV1 greater than or equal to 70% predicted normal and a provocative concentration of methacholine (MCh) required to decrease their FEV1 by 20% (PC20) less than or equal to 4 mg/ml. On each study day, FEV1 was within 10% and PC20 within one doubling-dose of the initial visit. Patients received either placebo, salbutamol 200 micrograms, formoterol 12 micrograms, or formoterol 24 micrograms by metered-dose inhaler. FEV1 and PC20 were measured repeatedly over 12 h. After salbutamol, peak FEV1 was 120% of baseline at 30 min and returned to baseline in 3 h. After formoterol (12 or 24 micrograms) peak FEV1 was 118% at 3 h and remained above baseline for at least 12 h. Protection from MCh by both doses of formoterol was significantly better than by salbutamol. Protection from formoterol 12 and 24 micrograms at 12 h was equivalent to that from salbutamol at 3 h. The PC20 of four children 48 h after formoterol 24 micrograms was more than twice their baseline PC20. Formoterol by inhalation is potent and long-acting and provides significantly better antiasthma protection than salbutamol.