Patlogar JE, Tansey C, Wiebe M, Hybki GC, Trostel T, Murphy LA, et al. A prospective evaluation of oral Yunnan Baiyao therapy on thromboelastographic parameters in apparently healthy cats. J Vet Emerg Crit Care. 2019 Nov 1;29(6):611–5.
Yunnan Baiyo (YB) is a Chinese herbal remedy that is used to treat bleeding. It is used both orally and topically to achieve hemostasis and promote coagulation in situations of bleeding tumors, trauma, post surgical biopsy (ie in rhinoscopy), and in other situations. There is some evidence in both humans and animals of decreased clotting times both in vitro and in vivo. Thromboelastography (TEG) is a laboratory technique that allows global evaluation of hemostasis, and could be useful in the determination of the efficacy of YB.
The purpose of this study was to determine the effects of YB on TEG parameters in cats, with a secondary goal of assessing for side effects of medication administration. The study was designed as a prospective, uncontrolled, clinical trial.
Cats were eligible for enrollment if they were >12m of age, not receiving any medications other than parasite control, and were free of cardiac disease on echocardiography. Baseline blood samples were collected for CBC, fibrinogen concentration, and TEG. Cats were then administered 250mg YB orally twice daily for 1 week, and blood was collected again 60-90 minutes after YB administration. Owners filled out a survey regarding adverse events.
20 cats were enrolled in the study, of which 2 were excluded for cardiomyopathy and one for a cystic mediastinal mass. One cat developed vomiting after 3 days of administration and dropped out of the study. Of the 16 cats that completes the study, 11 were neutered male and 5 spayed female with a median age of 54 months (18-102).
There was a statistically (though likely not clinically) significant decrease in RBC and hematocrit values pre- and post- YB therapy, though no cats developed anemia. There was no significant difference in any TEG parameter after YB administration.
The only clinical side effect reported in this study was vomiting that occurred in 3 cats (17.7%). It is not clear if this vomiting was due to YB administration or coincidental, however in one cat it was severe enough to require withdrawal from the study.
There were multiple limitations present in this study. While it was prospective in nature, it was uncontrolled and involved a small number of cats (especially when considering exclusions and drop-outs). The dose of YB chosen was based on anecdote and not on pharmacokinetic data regarding the active components. While TEG is an evaluator of global coagulation, it has limitations, and further analysis (ie of platelet function) may find alterations not detected by TEG.
Despite these limitations, this study demonstrated that the administration of YB to cats is associated with vomiting in ~17% of animals, results in a drop in hematocrit (presumably undesirable in animals at risk of bleeding), and has no effect on TEG parameters. While the authors do not directly state as such, the results of this study suggest that oral Yunnan Baiyo administration in cats at risk of bleeding should be avoided until further research show otherwise. MK
Chew E. Effects of Yunnan Bai Yao on blood platelets: an ultrastructural study. Comp Med EastWest. 1977;5:169-175
Ogle CW,Dai S, Cho CH. The hemostatic effects of orally administered Yunnan Bai Yao in rats and rabbits. Comp Med East West. 1977;5:155- 160.
Wirth KA, KowK, SaluteME, et al. In vitro effects of Yunnan Baiyao on canine hemangiosarcoma cell lines. Vet Comp Oncol. 2016;14:281-284