Therapeutic ratio of hydrofluoroalkane and chlorofluorocarbon formulations of fluticasone propionate

Abstract

Objectives: To compare the therapeutic ratio of chlorofluorocarbon (CFC) and hydrofluoroalkane-134a (HFA) formulations of fluticasone propionate (FP).

Methods: We performed a randomized, placebo-controlled, crossover study comparing 6 weeks of treatment with FP using 500 micro g/d and 1,000 microg/d formulations of CFC and HFA. The primary end points were provocative dose of methacholine causing a 20% fall in FEV1 (PD20) and overnight urinary cortisol/creatinine excretion.

Results: Eighteen patients with mild-to-moderate asthma and geometric mean (SEM) PD20 of 82.3 micro g (19.2 micro g) completed the study. All treatments significantly improved PD20 values and morning peak expiratory flow vs placebo, while 1,000 microg/d was significantly better than 500 microg/d for the CFC formulation of FP (CFC-FP) but not the HFA formulation of FP (HFA-FP). Only 1,000 microg/d of CFC-FP caused significant suppression of overnight urinary cortisol/creatinine compared to placebo. There were no differences between formulations at either dose.

Conclusions: The increased airway benefit with CFC-FP > 500 microg/d was offset by greater systemic effects. Although HFA-FP had fewer systemic effects than CFC-FP at 1,000 microg/d, there was no benefit to increasing HFA-FP to > 500 microg/d.