Efficacy and safety of levosalbutamol in patients with mild to moderate asthma compared with racemic salbutamol: results of a crossover placebo-controlled study

Aim. Effectiveness and safety of levosalbutamol metered dose inhaler (MDI) in comparison with placebo and salbutamol.

Materials and methods. In this multicenter, randomized, placebo-controlled, 3-period crossover study, all asthma patients (n=91) received levosalbutamol (90 mcg), salbutamol (180 mcg), and placebo using standard MDI. Pulmonary function testing – forced expiratory volume in the first second (FEV₁) and forced vital capacity (FVC) – was performed 45 and 15 minutes before and 5, 10, 15, 30, 60, 90, 120, 180, 240, 300 and 360 minutes after dosing. The primary efficacy endpoint was the baseline-corrected area under FEV₁ curve from 0 to 6 hours (AUC_(0–6h)). Secondary endpoints were the baseline adjusted FEV₁ and FVC peak values, as well as the onset of drug action.

Results. The FEV₁ AUC_{0–6 hours} analysis confirmed similar bronchodilatory levosalbutamol and salbutamol effect (p=0.595), significantly improved compared with placebo (p<0.001). The peak values of FEV₁ and FVC after levosalbutamol or salbutamol dosing were similar (p=0.643) and significantly higher compared with placebo group (p<0.001). The active therapy effect was observed 5 minutes after dosing and throughout the entire observation period up to 6 hours, however, there was some tendency towards a longer duration of action of levosalbutamol compared to salbutamol. Levosalbutamol was well tolerated by patients; after levosalbutamol dosing twiсе fewer adverse reactions were observed compared to salbutamol.

Conclusion. Levosalbutamol at a 90-mcg dose showed efficacy similar to that of salbutamol at a dose of 180 mcg, assosiated with a good safety profile.