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The Hazards of Chinese Herbs

A look at the research.


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Seeds from the strychnine tree contain two deadly alkaloids.

WASANAJAI/SHUTTERSTOCK

Jen Hsou Lin, DVM, Ph.D., and Richard Panzer, DVM, MS—both recognized for their contributions to Chinese medical literature—published a paper in 1994 on the “Use of Chinese Herbal Medicine in Veterinary Science: History and Perspectives.”1 The authors exhorted their colleagues to subject herbal medicine to “testing by the methods of Western veterinary science.” They identified research as “the only way to reveal the clinical value of Chinese herbal medicine.” 

In addition, Drs. Lin and Panzer called for a “strict examination” of claims made by Traditional Chinese Veterinary Medical (TCVM) providers regarding its effectiveness.

Twenty-two years later, how much progress have we made?

Need for Scrutiny 

Scientific investigations require testing of quantitative, not qualitative, outcomes. Moreover, one would need to know the exact ingredients, sourcing, preparation, quality and purity of the products tested in order to ensure batch-to-batch similarity for both research and field applications.

Unfortunately, veterinary Chinese herbal textbooks, course descriptions and journal publications continue to invoke metaphors to explain products’ actions.1 For example, one veterinary Chinese herbology text opens by stating: “By understanding the properties of Chinese herbal medicines, a practitioner can predict their actions and prescribe the appropriate herbal formula for a particular clinical condition. A variety of characteristics is used to describe Chinese herbal medicines. These include an herb’s temperature/energy, taste, direction of energy and channels entered.” 

While learning in this fashion may seem exotic and imaginative, it does little to prepare practitioners for rigorous research.

Enter Acupuncture 

To wit, three researchers from Taiwan and a U.S. veterinary school studied the effects of two herbal formulae and acupuncture for six French bulldogs with paraparesis secondary to spinal cord compression.2 Every dog had been referred on an emergent basis and all but one had received unspecified medications prior to their arrival. According to the authors, all dogs “were successfully treated with TCVM and responded rapidly within four treatments.” In this study, “TCVM” meant acupuncture and Chinese herbs. 

The value of acupuncture for patients after spinal cord injury has been discussed previously in several columns.3-5 But incorporating two Chinese remedies alongside acupuncture made it impossible to identify their relative risk or benefit for the dogs in this case series. Nonetheless, this is common practice among TCVM practitioners. 

Their choice of formulae for this condition was typical as well. As the authors indicated, “Chinese herbs consisted of Double P II. According to TCVM, the treatment principles of Double P II are to break down stasis in the spine, move Qi and relieve pain. The Bu Yang Huan Wu Tang tonifies Qi and smooths the channels.”

A Few Questions 

The researchers employed scientific terminology to detail the neurophysiologic changes that occur with acupuncture, so why did they resort to imprecise metaphors when speaking about the actions of Double P II and Ba Yang Huang Wu Tang? Were they never taught the modern pharmacology of the Chinese herbs? Did they not consider the actual mechanisms of action of pharmacologically active plant compounds important to include in a scientific publication? Wouldn’t one want to know more about the risks of negative effects and herb-drug interactions as well?

At the very least, in order for the reader to assess the relative safety of a Chinese herbal mixture, the authors should have disclosed not only the ingredients but also the amount of each one. However, they couldn’t because the manufacturer keeps the product’s exact makeup a secret.

This merely adds to the confusion about Double P II and its contributions to the outcomes.

Translation: Strychnine 

Here’s what we do know:

The fourth ingredient listed is strychnos, or Ma Qian Zi. The TCVM “action” listed states that it “moves Qi” and “relieves pain.” Imagine if all that we were taught in veterinary school was that carprofen moved qi and relieved pain. Would that be sufficient?

Upon further examination, one would learn that strychnos, or Strychnos nux-vomica, refers to the strychnine tree. The tree’s seeds, the part of the plant used in Chinese herbs, contain the two deadly alkaloids, strychnine and brucine.6 

Strychnine is an excitatory neurotoxin that, depending on the dose, can cause nervousness, neck pain, muscle spasms, trismus, continuous convulsions and death. It is excreted slowly, and circulating levels become cumulative over time.

Strychnos nux-vomica appears in the U.S. Food and Drug Administration’s Poisonous Plant Database.7 According to WebMD, “No one should take nux vomica, but certain people are especially at risk for toxic side effects. … The strychnine in nux vomica can cause liver disease or make liver disease worse. Don’t use it.”8 

Another ingredient in Double P II is aconite (Huang Qi), also known as monkshood. Severe poisoning can occur after ingestion of the wild plant as well as after consumption of an herbal decoction made from its roots.9 Patients poisoned by aconite exhibit neurologic, cardiovascular and gastrointestinal disturbances. Refractory ventricular arrhythmias and asystole constitute the main causes of death from aconite overdose. 

And yet, the authors discussed none of these dangers in their paper, only citing that Double P II treats pain and moves Qi. They failed to describe potential interactions that could occur between its neurotoxic and cardiotoxic contents and pharmaceuticals that treat pain, muscle tension and wind-up.

They did not mention comorbidities that might be present in any of the test subjects. They only stated that all dogs received the same dose and all improved.

Might that inspire other veterinary practitioners to follow suit and prescribe Double P II without knowing exactly what it contains, let alone the damage it could do? Such are the risks of veterinary herbal practice based on metaphors instead of science.

References

  1. Lin JH and Panzer R. “Use of Chinese Herbal Medicine in Veterinary Science:  History and Perspectives.” Rev Sci Tech Off Int Epiz. 1994;13(2):425-432.
  2. Xie H and Preast V (eds.). “Xie’s Chinese Veterinary Herbology.” Ames, IA: Wiley-Blackwell, 2010, p. 1.
  3. Liu CM, Holyoak GR, and Lin CT. “Acupuncture Combined With Chinese Herbs for the Treatment in Hemivertebral French Bulldogs With Emergent Paraparesis.”  Journal of Traditional and Complementary Medicine.  2016;6:409-412.
  4. Robinson N. “Why the Standards of Care for Spinal Cord Injuries Are Changing.” Veterinary Practice News.  May 16, 2016. Accessed at http://www.veterinarypracticenews.com/why-the-standards-of-care-for-spinal-cord-injuries-are-changing on 10-31-16.
  5. Robinson NG. “Laser Therapy May Work on TL IVDD.” Veterinary Practice News. March 11, 2010. Accessed at http://www.veterinarypracticenews.com/March-2010/Laser-Therapy-May-Work-On-TL-IVDD-0 on 10-31-16.
  6. Robinson N. “Got a Spinal Cord Injury? Get Acupuncture!” Veterinary Practice News. Nov. 2, 2015.  Accessed at http://www.veterinarypracticenews.com/got-a-spinal-cord-injury-get-acupuncture on 10-31-16.
  7. WebMD. “Nux Vomica.” Accessed at http://www.webmd.com/vitamins-supplements/ingredientmono-58-nux%20vomica.aspx?activeingredientid=58&activeingredientname=nux%20vomica on 10-31-16.
  8. U.S. FDA website. FDA Poisonous Plant Database. “Strychnine Poisoning From the Use of a Cambodian Traditional Remedy.” Accessed at http://www.accessdata.fda.gov/scripts/Plantox/Detail.CFM?ID=29744 on 10-31-16.
  9. WebMD. “Nux Vomica.” Accessed at http://www.webmd.com/vitamins-supplements/ingredientmono-58-nux%20vomica.aspx?activeingredientid=58&activeingredientname=nux%20vomica on 10-31-16.
  10. Chan TY. “Aconite poisoning.” Clin Toxicol. 2009;47(4):279-285.

Dr. Narda Robinson is president and CEO of CureCore Integrative Medicine and Education Center in Fort Collins, Colo. Columnists’ opinions do not necessarily reflect those of Veterinary Practice News. 

Originally published in the December 2016 issue of Veterinary Practice News. Did you enjoy this article? Then subscribe today! 

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