A comparison of the bronchodilatory effect of 50 and 100 microg salbutamol via Turbuhaler and 100 microg salbutamol via pressurized metered dose inhaler in children with stable asthma.

AIM: The aim of the study was to compare the efficacy of single doses of salbutamol Turbuhaler (50 and 100 microg), salbutamol pressurized metered dose inhaler (pMDI) (100 microg) and placebo in children with stable chronic reversible airway obstruction. Primary efficacy variable (FEV1-av) was calculated as the area under the curve of forced expiratory volume in one second (FEV1) (AUC, 0-4 h) and divided by the observed time.

DESIGN: The study was of a randomized, single-dose, crossover and double-blind design. Seven centres participated. FEV1 was measured pre-dose and at 15 min, 0.5, 1, 1.5, 2, 3 and 4 h post study dose.

PATIENTS: Forty asthmatic children (9 girls) with a mean age of 9 years (range: 6-12), mean FEV1 of 1.6 l (range: 0.9-2.4) and a mean FEV1 in percentage of predicted normal value of 80% (range: 61-109) were randomized into the study. The mean reversibility 30 min after inhaling 2x100 microg salbutamol from pMDI was 20% (range: 9-45) or 15% (range: 8-27) in percentage of predicted normal value.

RESULTS: The mean FEV1-av was 1.63 l for placebo, 1.71 l for 50 microg salbutamol Turbuhaler, 1.76 l for 100 microg salbutamol Turbuhaler and 1.76 for 100 microg salbutamol pMDI. Corresponding values for maximum FEV1 were 1.76, 1. 85, 1.87 and 1.87 l, respectively. There were no statistically significant differences between the active treatments in FEV1-av or maximum FEV1. All active treatments were significantly better than placebo.

CONCLUSION: No significant differences in bronchodilating effect between 50, 100 microg salbutamol Turbuhaler and 100 microg salbutamol pMDI in children, aged 6-12 years, with stable asthma could be demonstrated. All active treatments were significantly better than placebo.