AIM: Prescription of inhaled corticosteroids to children with asthma is recommended at half the nominal dose of adults in order to reduce the risk of systemic side effects. However, there is a lack of pharmacokinetic trials supporting such dose reduction regimens. Therefore, we aimed to compare the systemic exposure to the active ingredients of a fixed dose combination of beclometasone-dipropionate (BDP) and formoterol after dry powder inhaler (DPI) administration in children, adolescents and adults. METHODS: The pharmacokinetic profiles of formoterol and beclometasone-17-monopropionate (B17MP; active metabolite of BDP) were evaluated over 8 h from two independent studies comprising children (6-11yrs, n = 27), adolescents (12-17 yrs, n = 28) and adults (≥18 yrs, n = 30) receiving a single, fixed dose of BDP/formoterol (children: 200 μg/24 μg, adolescents and adults: 400 μg/24 μg) via DPI. RESULTS: The systemic exposure (AUC) for children versus adults was almost doubled for formoterol and similar for B17MP despite the halved BDP dose administered in children. In adolescents the AUC for formoterol and B17MP were approximately one third higher than in adults for both compounds. Upon normalization for the BDP/formoterol dose in the three populations the AUC and peak concentration (C(max)) correlated inversely with age and body surface area of the patients (r ≤ -0.53; p