Objective: To assess the change in bronchial response to cumulative doses from two beclomethasone dipropionate metered-dose inhalers (MDI), each using chlorofluorocarbon (CFC) propellants, in asthma patients previously showing falls in forced expiratory volume in 1 s (FEV1) shortly after exposure to beclomethasone MDI.
Methodology: A total of 18 patients were randomized to a single-blind, three-period cross-over treatment regimen, whereby each was administered increasing doses of control mixture (containing surfactant and CFC propellants) or beclomethasone, formulated as either Becloforte or Respocort (250-1000 microg per dose; cumulative dose 2000 microg). Bronchial response was measured by comparison of FEV1 values pre- and post-inhalation.
Results: Respocort formulation produced the least post-dose mean maximum reduction in FEV1 (0.36 +/- 0.17 L; 14.3 +/- 7.2% of baseline FEV1), while the reduction caused by the control was similar (0.40 +/- 0.18 L; 16.2 +/- 9.9% of baseline FEV1). Becloforte produced a significantly greater maximum reduction in FEV1 than Respocort (0.55 +/- 0.32 L, P = 0.003; 22.0 +/- 15.3% of baseline FEV1, P = 0.005). No serious adverse events were reported, but four patients experienced falls in FEV1 of greater than 15% (three on Becloforte, one using the control).
Conclusion: The incidence of falls in FEV1 following use of beclomethasone MDI was low and generally not serious even in a selected population. The Becloforte preparation produced significantly more post-dose bronchoconstriction than the Respocort formulation, perhaps because of differences in the composition of the surfactant and/or CFC propellant mixtures used to formulate each of the aerosols.