Inhaled and oral bronchodilator therapy in exercise induced asthma

Area of Science:

• Pulmonology
• Pharmacology
• Exercise Physiology

Background:

• Asthma is characterized by bronchoconstriction, often exacerbated by exercise.
• Beta-adrenergic stimulants are commonly used to manage asthma symptoms.
• Assessing the efficacy of different drug delivery methods is crucial for optimal asthma management.

Purpose of the Study:

• To compare the efficacy of oral terbutaline and fenoterol aerosol in preventing post-exercise bronchoconstriction in asthmatic subjects.
• To evaluate the impact of these beta-adrenergic stimulants on peak expiratory flow rates (PEFR).

Main Methods:

• 18 asthmatic subjects underwent serial exercise tests.
• Measurements of peak expiratory flow rate (PEFR) were recorded.
• Efficacy of oral terbutaline (5 mg) and fenoterol aerosol (400 µg) was assessed against placebo.

Main Results:

• Both terbutaline and fenoterol significantly elevated resting PEFR for at least four hours.
• Oral terbutaline did not alter the pattern of exercise response but increased PEFR values at 2, 4, and 6 hours post-administration.
• Fenoterol aerosol completely blocked post-exercise bronchoconstriction for up to four hours in most subjects.
• Bronchodilation occurred during exercise with both active drugs and placebo.

Conclusions:

• Fenoterol aerosol demonstrated superior efficacy in blocking exercise-induced bronchoconstriction compared to oral terbutaline.
• The route of administration (aerosol vs. oral) may influence the effectiveness of beta-adrenergic stimulants in preventing exercise-induced bronchoconstriction.
• Actual PEFR values, not just percentage changes, are important for evaluating bronchodilator efficacy.