This work was performed at the College of Veterinary Medicine, Athens, GA.
Effects of Clopidogrel and Aspirin on Platelet Aggregation, Thromboxane Production, and Serotonin Secretion in Horses
Article first published online: 8 DEC 2010
Copyright © 2010 by the American College of Veterinary Internal Medicine
Journal of Veterinary Internal Medicine
Volume 25, Issue 1, pages 116–122, January/February 2011
How to Cite
Brainard, B.M., Epstein, K.L., LoBato, D., Kwon, S., Papich, M.G. and Moore, J.N. (2011), Effects of Clopidogrel and Aspirin on Platelet Aggregation, Thromboxane Production, and Serotonin Secretion in Horses. Journal of Veterinary Internal Medicine, 25: 116–122. doi: 10.1111/j.1939-1676.2010.0647.x
- Issue published online: 11 JAN 2011
- Article first published online: 8 DEC 2010
- Submitted September 6, 2010; Revised October 5, 2010; Accepted October 13, 2010.
- Antiplatelet agents;
- SR 26334;
Background: Critically ill horses are susceptible to thrombotic disease, which might be related to increased platelet reactivity and activation.
Objectives: To compare the effect of oral clopidogrel and aspirin (ASA) on equine platelet function.
Animals: Six healthy adult horses.
Methods: Horses received clopidogrel (2 mg/kg PO q24h) or ASA (5 mg/kg PO q24h) for 5 days in a prospective randomized cross-over design. Platelet aggregation responses to adenosine diphosphate (ADP) and collagen via optical aggregometry, and platelet secretion of serotonin (5HT) and production of thromboxane B2 (TXB2) by ELISA were evaluated. In horses receiving clopidogrel, high-performance liquid chromatography analysis for clopidogrel and its carboxylic-acid metabolite SR 26334 was performed.
Results: SR 26334 was identified in all clopidogrel-treated horses, although the parent compound was not detected. Clopidogrel resulted in decreases in ADP-induced platelet aggregation persisting for 120 hours after the final dose. ADP-induced platelet aggregation decreased from a baseline of 70.2 ± 14.7% to a minimum of 15.9 ± 7.7% 24 hours after the final dose (P < .001). Collagen-induced aggregation decreased from a baseline of 93 ± 9.5% to a minimum of 70.8 ± 16.9% 48 hours after the final dose (P < .001). ASA did not decrease platelet aggregation with either agonist. ASA decreased serum TXB2 from a baseline value of 1310 ± 1045 to 128 ± 64 pg/mL within 24 hours (P < .01).
Conclusions and Clinical Importance: Clopidogrel effectively decreases ADP-induced platelet aggregation in horses, and could have therapeutic applications for equine diseases associated with platelet activation.