Fluticasone Propionate via the Diskhaler or Hydrofluoroalkane-134a Metered-Dose Inhaler on Methacholine-Induced Airway Hyperresponsiveness

Abstract

s: To compare the effect of 4 weeks of treatment with fluticasone propionate (FP), 100 micro g bid, delivered either via the Diskhaler (GlaxoSmithKline; Middlesex, UK) or a hydrofluoroalkane (HFA)-134a pressurized metered-dose inhaler (pMDI) on airway responsiveness. A single-center, randomized, double-blind, double-dummy, placebo-controlled crossover study. Outpatients. Patients with mild asthma who had not received corticosteroids for 4 weeks prior to the study. FP, 100 micro g bid, via the Diskhaler, HFA-134a pMDI, or placebo for periods of 4 weeks. The primary efficacy variable was the provocative dose of methacholine causing a 20% fall in FEV(1) (PD(20)) at the end of each 4-week treatment period. The FP formulations were defined as equivalent if the treatment difference was within +/- 1 doubling dose of methacholine. Forty-seven patients were included in the per-protocol population. The baseline PD(20) geometric mean was 0.21 mg, which increased to 0.55 mg with FP via the HFA-134a pMDI and to 0.68 mg with FP via the Diskhaler. The treatment difference between adjusted means was - 0.16 doubling doses (95% confidence interval, - 0.62 to 0.31 doubling doses; p = 0.503). Both significantly decreased airway responsiveness compared to placebo (p < 0.001), and also significantly increased lung function with no difference between the two active groups. FP was well tolerated with few adverse events and no effect on serum cortisol levels. FP delivered via the HFA-134a pMDI is equivalent to FP via the Diskhaler in reducing airway responsiveness.