Flunisolide hydrofluoroalkane with integrated spacer for treating asthma: an updated review

Flunisolide hydrofluoroalkane (HFA) with integrated spacer is the most recent reformulated inhaled corticosteroid (ICS) for asthma available in the United States. It is the only product that combines a corticosteroid extrafine aerosol with a built-in spacer. The potential clinical benefit of the flunisolide HFA formulation and its integrated spacer for treating persistent asthma was assessed through a comprehensive review of the published literature and data from the past 10 years focusing on (1) flunisolide, the molecule, and the impact of the HFA reformulation; (2) updated information on the anti-inflammatory response to flunisolide HFA, particularly in the distal airways; and (3) the usefulness of an integrated spacer. Flunisolide HFA was found effective and safe in clinical studies and comparable with the chlorofluorocarbon (CFC) formulation, but at about one-third the dose of flunisolide CFC, likely reflecting both the device and the particle size of the reformulated product. Compared with the CFC formulation, the extrafine aerosol and smaller particle size of flunisolide HFA substantially increased pulmonary deposition and decreased oropharyngeal deposition. The integrated spacer further enhanced the pulmonary/oropharyngeal deposition ratio. Examination of lung biopsy specimens indicated a favorable anti-inflammatory response to flunisolide HFA in peripheral airways. Pediatric studies showed no significant effects on growth. The data indicate that flunisolide HFA is a safe and effective maintenance therapy for asthma patients. The integrated spacer may provide an added advantage for patients, especially those who may be more likely to experience adverse effects of ICSs, both local and systemic, including children susceptible to adverse effects on growth.