Fluticasone propionate aerosol is more effective for prevention than treatment of recurrent airway obstruction.

The research finds that an aerosol form of fluticasone propionate, when inhaled by horses with recurrent airway obstruction, is more effective when used as a preventive measure rather than as a treatment after an obstruction has occurred.

Objectives and Methodology

The researchers sought to compare the effectiveness of two drugs, fluticasone propionate (FP) and dexamethasone (DEX), in managing recurrent airway obstruction (RAO) in horses. In the experiment, nine horses with RAO were subjected to two trials with FP and DEX.

• In the first trial, the team aimed to assess the efficacy of 3-day treatment doses of FP and DEX when an RAO exacerbation has occurred. They utilized both a low-dose (3mg) and a high-dose (6mg) of FP for comparison.
• In the second trial, the team investigated the preventative efficacy of FP and DEX against acute exacerbations of RAO, comparing the effects of treatment to a control group that received no treatment.

The efficacy of the treatments was evaluated based on changes in pleural pressure, serum cortisol levels, bronchoalveolar lavage (BAL) cytology, and subjective scores for respiratory distress and lameness in the horses.

Key Findings

The findings showed that both DEX and the high-dose FP (6mg) significantly reduced pleural pressure within 48 and 72 hours respectively. However, the lower-dose FP (3mg) yielded no significant impact.

• DEX reduced the serum cortisol levels more than FP did.
• In the prevention trial, both DEX and the high-dose FP effectively prevented an increase in pleural pressure that was noticed in untreated horses.
• Either treatments did not affect the bronchoalveolar lavage fluid cytology, and there were no signs of laminitis—the inflammatory disease that causes lameness in horses.

Conclusions

The study concludes that inhaled fluticasone propionate (FP), specifically dosed at 6mg, is as effective as dexamethasone (DEX) in preventing acute exacerbations of recurrent airway obstructions, indicating that lower doses merit further evaluation. However, when used for treatment, the high-dose FP lacks the efficacy of DEX.