Abstract
Equal efficacious doses of the inhaled corticosteroids can result in significant differences in systemic effects due to differences in their pharmacokinetic profile. The purpose of this study was to evaluate a model to compare systemic activity of inhaled corticosteroids given in topically equipotent doses in children. Systemic effects were measured by 24-hour urinary free cortisol (UFC) and a.m. and p.m. serum osteocalcin. Efficacy was monitored by a.m. and p.m. exhaled nitric oxide (eNO) and a.m. peak expiratory flow (PEF). Twenty-one children, 6-16 years old on inhaled corticosteroids at ≥400 μg/day beclomethasone dipropionate (BDP) equivalent were placed on BDP for a 2-week, open-label, run-in, baseline period. Patients were then randomized into a double-blind, double-dummy, crossover trial for two 3-week periods of equipotent doses of fluticasone propionate (FP) or triamcinolone acetonide (TAA) as defined by the NHLBI Expert Panel Report 2. At the end of baseline and each treatment phase patients were hospitalized for sample collection. UFC was corrected for creatinine (Cr) and body surface area (BSA). No difference was found in the last 7 days of a.m. PEF between treatments. The mean log of p.m. eNO was significantly lower for FP than TAA (25.9 vs. 35.0 ppb, p = 0.04). No difference between treatments was seen in UFC/Cr. When UFC was corrected for BSA, FP resulted in higher excretion compared to TAA (20.9 vs. 16.5, p = 0.035). Mean serum osteocalcin did not differ between treatments. TAA produced greater suppression of some but not all markers of systemic activity than did FP. In addition, there was some suggestion of a lower anti-inflammatory effect for TAA, suggesting that TAA has a lower therapeutic index than FP. Further studies at higher doses will be needed to confirm these findings. Medium doses of ICSs do not produce clinically important suppression of adrenal axis or bone metabolism in children.
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