Background: Inhaled corticosteroids are currently recommended as first-line therapy for the long-term control and management of persistent asthma. Flunisolide hydrofluoroalkane (HFA) is a new formulation of the corticosteroid flunisolide that is delivered by a metered-dose inhaler containing an HFA propellant. HFA replaces the chlorofluorocarbon (CFC) propellant of the previous formulation, producing aerosols of smaller average particle size.
Objective: This article reviews the physical and pharmacologic properties, deposition profile, and potential clinical benefits of flunisolide HFA for the treatment of asthma.
Methods: Data included in this review were found via MEDLINE (search term, flunisolide HFA).
Results: Flunisolide HFA has a mass median aerodynamic diameter (MMAD) of 1.2 microm, smaller than the 3.8 microm MMAD of the CFC formulation. Compared with flunisolide CFC, more of each flunisolide HFA dose reaches the lungs and less is deposited in the oropharynx. In addition, scintigraphic studies have found that the extra-fine particle size of flunisolide HFA gives it better access to small airways. In short- and long-term clinical studies, flunisolide HFA has been found to significantly increase pulmonary function relative to placebo. Although not statistically superior to the previous CFC formulation, flunisolide HFA exhibited small improvements in secondary efficacy measures, such as as-needed albuterol use and asthma symptoms, relative to flunisolide CFC. Furthermore, research suggests that the new HFA formulation has a low risk of systemic corticosteroid effects (eg, hypothalamic-pituitary-adrenal axis suppression, growth inhibition in children). Also, lower levels of oropharyngeal deposition, such as those seen with flunisolide HFA, are associated with lower incidence of local effects (eg, candidiasis).
Conclusion: Flunisolide HFA offers effective asthma control with a high level of tolerability in an extra-fine particle formulation that distributes corticosteroid to all areas of the lung, including small airways.