Original salbutamol versus similar salbutamol in children with asthma. A randomized controlled double-blind study

Introduction. According to some clinical evidence original salbutamol should be more effective than a similar one in reverting acute asthma symptoms. Objective. To assess acute pharmacodynamic responses of both drug products in children with asthma, and to establish if bronchodilator response, determined by forced expiratory volume in the first second (FEV1) differs between groups treated with original and similar salbutamol. Design. Prospective, randomized, controlled, double blind study. Patients and methods. One hundred and twenty six children (63 male, age 9.18 +/- 2.83 years), were included. They received a single 20 drop (5 mg) dosis of original or similar salbutamol in inhalation solution diluted in 2 ml saline solution. Pre-and post-beta 2 FEV1 were compared intra-and inter-groups, at baseline and after 30 minutes. The weight of salbutamol drops was calculated by gravimetry, the concentration was estimated by chromatography, and number of drops was determined by container. Results. Bronchodilator response between pre- and post-beta(2) FEV1 was 225 ml (CI 95% 164-286) and 224 ml (CI 95% 163-284) for original and similar salbutamol, respectively (p < 0.0001). Difference delta was 1.3 ml (CI 95% -86+83) (p=0.97). Drop weight (X +/- SD, CV) was 364.75 mg (+/- 6.01, 1.65), and 543.88 mg (+/- 56.09, 10.31) (p < 0.0007) for original and similar salbutamol, respectively. Conclusions. No significant difference was found between bronchodilator responses of original and similar salbutamol.