From Cat
Figure showing platelet aggregation (PA) in 9 healthy cats before and after a 3-day clopidogrel treatment of 18.75 mg q 24 hrs

Thienopyridines, such as Clopidogrel (Plavix), are anti-platelet aggregation drugs which irreversibly inhibit the binding of adenine diphosphate (ADP) to specific platelet ADP receptors, thereby inhibiting clotting. This ADP receptor blockade impairs platelet release reaction and ADP-mediated activation of GPIIb/IIIa, thereby reducing the aggregation response. Clopidogrel (Plavix; Sanofi-Aventis, Laval, Quebec), a thienopyridine, is readily available and has been evaluated in healthy cats.

In comparison to aspirin and cilostazol, clopidogrel causes prolonged bleeding time in cats as does aspirin, but not cilostazol, which appears to have antithrombotic effects without altering clotting time in cats[1].

Clopidogrel, at dosages of 18.75 mg orally every 24 hrs appear to be well tolerated in cats and results in significant anti-platelet effects[2][3].

Its primary use in cats is for prevention or minimisation of recurrence of aortic thromboembolism associated with various heart diseases such as cardiomyopathy and mitral valve dysplasia. It appears limited in its capacity as a thrombolytic agent[4]. However, clinical trial demonstrate that clopidogrel is superior to aspirin with a lower recurrence rate and longer time to recurrent aortic thromboembolism[5]


  1. Joong-Seok Kim MDa, Kwang-Soo Lee MDa, , , Yeong-In Kim MDa, Yoshiko Tamai MDb, Reiko Nakahata MDb and Hideki Takami MD (2004) A randomized crossover comparative study of aspirin, cilostazol and clopidogrel in normal controls: analysis with quantitative bleeding time and platelet aggregation test. Journal of Clinical Neuroscience 11(6):600-602
  2. Hogan DF, Andrews DA, Green HW, Talbott KK, Ward MP, Calloway BM. (2004) Antiplatelet effects and pharmacodynamics of clopidogrel in cats. J Am Vet Med Assoc 225:1406–1411
  3. Teuber M & Mischke R (2016) Influence of a low dosage of clopidogrel on platelet function in cats as measured by the platelet function analyser PFA-100 and the multiplate analyser. Res Vet Sci 109:149-156
  4. Hogan, DE & Ward, MP (2004) Effect of clopidogrel on tissue-plasminogen activator-induced in vitro thrombolysis of feline whole blood thrombi. Am J Vet Res 65(60):715-719
  5. Hogan DF (2017) Feline Cardiogenic Arterial Thromboembolism: Prevention and Therapy. Vet Clin North Am Small Anim Pract. 47(5):1065-1082