Comparative study of the bronchodilator efficacy and adverse effects of salbutamol and hyoscine butylbromide in horses with severe asthma.
Authors: Mozo Vives Berta, Mainguy-Seers Sophie, Lavoie Jean-Pierre
Journal: Journal of veterinary internal medicine
Summary
# Editorial Summary Mozo Vives, Mainguy-Seers, and Lavoie compared inhaled salbutamol (1000 µg) and intravenous hyoscine butylbromide (150 mg) in six horses experiencing acute severe asthma exacerbations using oscillometric lung function measurements and repeated assessments over 180 minutes. Both agents achieved similar immediate bronchodilation, yet salbutamol demonstrated superior duration—airway reactance remained significantly improved at 180 minutes with salbutamol (0.040 Kpa/L/s), whereas HBB returned to baseline within 30 minutes, and pulmonary resistance showed comparable divergence between the two treatments. Notably, HBB induced clinically concerning adverse effects including tachycardia (mean increase of 13.0 bpm at 30 minutes) and marked reduction in intestinal borborygmi (score reduction of 2.8 points), whilst salbutamol produced neither cardiovascular nor gastrointestinal changes of statistical significance. For practitioners managing acute asthma episodes in horses, these findings support preferential use of inhaled salbutamol over parenteral hyoscine butylbromide, particularly given the longer bronchodilatory window and absence of complications associated with anticholinergic activity—considerations that become increasingly relevant when treating compromised animals where cardiovascular stress or ileal impaction pose additional risks.
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Practical Takeaways
- •For acute asthma exacerbations in horses, salbutamol inhalation provides sustained bronchodilation over 3 hours with minimal side effects, making it the preferred first-line agent
- •Avoid HBB for routine asthma management due to tachycardia and reduced gut motility; reserve for situations where its anticholinergic properties may be specifically beneficial
- •Inhaled salbutamol offers advantages over IV HBB in terms of local delivery, longer effect duration, and safer adverse effect profile for equine asthma cases
Key Findings
- •Both salbutamol (1000 μg inhaled) and hyoscine butylbromide (150 mg IV) produced similar initial bronchodilation in horses with severe asthma exacerbation
- •Salbutamol demonstrated longer duration of bronchodilation, with improved reactance persisting at 180 minutes compared to HBB which returned to baseline by 30 minutes
- •HBB caused significant cardiovascular effects (mean heart rate increase of 13.0 bpm at 30 minutes, P=0.002) and gastrointestinal effects (mean auscultation score reduction of 2.8, P<0.0001) whereas salbutamol showed no significant adverse effects
- •Salbutamol is preferable to HBB for bronchodilation in asthmatic horses due to superior duration of action and absence of gastrointestinal and cardiovascular side effects