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Aims: To investigate dose proportionality, dosing frequency, and ethnic aspects of the pharmacokinetics of bambuterol in asthmatic children, and to discuss the relationship with previous observations in adults., Methods: Forty-eight children in four different studies completed two double-blind bambuterol treatments each (daily doses of bambuterol hydrochloride): 12 preschool (5 mg x 2 vs 10 mg) and 12 school (10 mg vs 20 mg) Caucasians, 12 preschool (2.5 mg vs 5 mg), and 12 school (10 mg vs 20 mg) Orientals. Peak plasma concentrations and dosing interval area under curve (AUC) of bambuterol and the active metabolite terbutaline were assessed at steady state. Treatment differences were analysed statistically within each study. Differences between the studies and the relation to steady-state AUC in adults were described., Results: Dose proportionality was seen for terbutaline but not for bambuterol. Twice-daily dosing (2 x AUC(0,12 h)) could not be shown to differ from once-daily dosing (AUC(0,24 h)) in the preschool Caucasians. Mean AUC of terbutaline was 128 and 242 nmol l-1 h in the preschool Caucasians (5 mg/12 h; 10 mg/24 h), 213 and 406 nmol l-1 h in the Caucasian school children (10 mg; 20 mg), 87.4 and 202 nmol l-1 h in the Oriental preschool children (2.5 mg; 5 mg), and 356 and 640 nmol l-1 h in the Oriental school children (10 mg; 20 mg). Oriental school children had higher plasma concentrations of bambuterol and terbutaline than Caucasian school children. The strict ethnic implication of the difference could not be elucidated, because demographic data were not perfectly matched. Terbutaline AUC was only moderately increased in the Caucasian school children compared with Caucasian adults. The increase was more pronounced in Oriental children and in some preschool Caucasians. The highest concentration of terbutaline, 58 nmol l-1, was seen in an Oriental school child after a 20 mg dose., Conclusions: Caucasian school children can be given bambuterol hydrochloride very much as Caucasian adults, 10 or 20 mg once daily, but Oriental preschool and school children plus preschool Caucasians should be given lower doses.

Background: Pulmonary administration of beta 2-agonists by means of pressurized metered dose inhaler is widely used in the treatment of asthma. Young children have difficulties in using these inhalers unless a spacer device is used. To overcome this problem inspiratory flow driven dry powder inhalers have been developed., Objective: The aim of this study was to compare the efficacy and safety of the two powder inhalers Bricanyl Turbuhaler (terbutaline sulphate 0.5 mg t.i.d.) and Ventolin Rotahaler (salbutamol 0.4 mg t.i.d.) in 20 children 2 to 6 years old with mild to moderate asthma., Methods: The study had an open randomized crossover design with 1 week run-in without treatment and the two treatment periods of 2 weeks each. Efficacy was measured with peak expiratory flow determination, asthma symptom scores, and need for rescue medication. Adverse events were recorded., Results: Peak expiratory flow increased significantly (P < .001) after both treatments. There were no statistically significant differences in peak expiratory flow, asthma symptom scores, need for extra inhalations, or adverse events between the devices. Most children (parents) preferred the Turbuhaler., Conclusion: Both Bricanyl Turbuhaler and Ventolin Rotahaler seem to be effective and well tolerated in the treatment of asthma in preschool children. Of special interest is that even the youngest children in the study group were able to use these powder inhalers.