Background: Secondary to the phase-out of chlorofluorocarbons (CFCs), the albuterol (Ventolin, GlaxoSmithKline, Uxbridge, Middlesex, United Kingdom) pressurized metered-dose inhaler (MDI) has been formulated in a non-ozone-depleting propellant, hydrofluoroalkane (HFA) 134a.
Objective: To compare the efficacy of albuterol HFA to albuterol CFC and placebo HFA in protecting patients from exercise-induced bronchospasm (EIB).
Methods: Randomized, double-blind, placebo-controlled, three-way crossover study in patients with documented EIB. Patients (n = 24) aged 18 to 45 years old received albuterol HFA or albuterol CFC, (total dose of 180 microg ex-actuator), or placebo HFA via an MDI, 30 minutes before a standardized exercise challenge. Serial forced expiratory volume in 1 second (FEV1) measurements were made 5 minutes before exercise and 5, 10, 15, 20, 25, 30, and 60 minutes postexercise. The primary outcome measure was the maximum percentage fall in FEV1 over the 60 minutes after exercise.
Results: The adjusted mean maximum percentage falls in FEV1 postexercise for albuterol HFA and CFC groups were 15.4% and 14.9%, respectively. The two formulations were comparable with a treatment difference of -0.5% (P = 0.848; 95% confidence interval, -5.3 to 4.4%). When compared with the fall in FEV1 for placebo (33.7%), both active treatments demonstrated a significantly smaller fall in FEV1 postexercise (P < 0.001). Safety profiles were similar among the three treatment groups.
Conclusions: The results provide assurance to prescribers that the formulation of albuterol in the non-ozone-depleting propellant HFA 134a has not affected its efficacy in the treatment of EIB in asthmatic patients. Single doses of albuterol HFA and CFC from an MDI are comparable in terms of efficacy and safety on a microgram per microgram basis.