Modulation of acute transient exercise-induced hypertension after oral administration of four angiotensin-converting enzyme inhibitors in normotensive horses.
Authors: Muñoz Ana, Esgueva María, Gómez-Díez Manuel, Serrano-Caballero Juan Manuel, Castejón-Riber Cristina, Serrano-Rodríguez Juan Manuel
Journal: Veterinary journal (London, England : 1997)
Summary
# Editorial Summary Exercise-induced hypertension is a normal physiological response in horses, but whether angiotensin-converting enzyme inhibitors (ACEIs) can moderate this elevation remains largely unexplored in normotensive animals. Researchers administered four different oral ACEIs—enalapril (2.0 mg/kg), quinapril (1.0 mg/kg), ramipril (0.2 mg/kg) and benazepril (0.5 mg/kg)—to six healthy horses alongside placebo controls, then measured systolic and diastolic blood pressure responses to a standardised treadmill exercise bout (8 m/s for 1 minute) performed 2 hours post-administration. Benazepril proved most effective at suppressing the exercise-induced systolic blood pressure surge, limiting the increase to just 4.2% compared with 67.6% in placebo trials, whilst quinapril and ramipril showed intermediate effects; diastolic pressure responses were more modest across all treatments, though benazepril again demonstrated the greatest attenuation. These findings suggest that benazepril at this dosage may have clinical applications in managing exercise-induced hypertension in horses, particularly those with underlying cardiovascular concerns or pre-existing hypertension, though practitioners should note that resting and pre-exercise blood pressures remained unchanged across all treatments, indicating these drugs do not artificially suppress normal baseline haemodynamics.
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Practical Takeaways
- •Benazepril at 0.5 mg/kg effectively modulates exercise-induced blood pressure spikes in horses, which may be relevant for managing hypertension-related performance or health issues in working horses
- •Among the four ACEIs tested, benazepril demonstrated superior efficacy and should be considered if pharmacological management of exercise-induced hypertension is indicated
- •The study was conducted on healthy normotensive horses at moderate exercise intensity; applicability to clinical disease or intense exercise remains unclear
Key Findings
- •Benazepril at 0.5 mg/kg achieved the highest serum ACE inhibition at 71.68%, compared to 39.4% for enalapril, 46.4% for quinapril, and 55.0% for ramipril
- •Systolic blood pressure increase in response to exercise was markedly reduced with benazepril (4.2% increase) compared to placebo (67.6% increase)
- •Diastolic blood pressure response to exercise was minimally affected by most ACEIs, with benazepril showing only 3.7% increase versus 20.6% in placebo
- •Resting and pre-exercise blood pressures were not significantly different across all five trials, indicating normotensive baseline conditions were maintained