Re: Herbal medicine and liver toxicity
The letter by Yoshida and colleagues [BCMJ 2017;59:348] reports on two patients with hepatotoxicity from herbal medicine (Chinese and Indian) requiring liver transplant and recommends regulation of herbal products.
Hepatitis due to Chinese herbs has been reported, including one fatal case where hepatitis was complicated by massive hepatic necrosis.[1] It was suggested that among the Chinese herbs, either Dictamnus dasycarpus or Paeonia spp could be the toxic agent.[2] I wonder if one of these two Chinese herbs is included in the list of the herbal products taken by the patients.
Besides hepatotoxicity, some Chinese herbal products may have cardiotoxicity and neurotoxicity as well as some other toxicities (the majority of the Chinese herbal products are without toxicity). Aconite and ephedra are two notable examples. Traditional Chinese medicine practitioners are well aware of the toxic nature of aconite (Aconitum species, Cao Wu, Chuan Wu). The cured/processed form, Fu Zi, after treatment, is considered safe. However, there is a case report of cardiac adverse reaction associated with Fu Zi.[3]
Ephedrine/Ephedra (Ma Huang) is the first complementary and alternative medicine banned by US Food and Drug Administration (US FDA) in 2004. However, Health Canada still allows its use with restriction less than that proposed by US FDA in 1997, some 20 years earlier. Health Canada should provide a higher standard of regulation.[4]
Patients with severe cardiotoxicity from aconites and ephedra may not be as fortunate as the two patients receiving liver transplants. The course may be too rapid and cardiac transplant may not be suitable or readily available as a form of management.
Patients using herbal products should report the use to their physicians who in turn enquire about the use of complementary and alternative medicine by the patients in history taking. This is to ensure potential adverse reaction can be identified.
I agree with the recommendation of Yoshida and colleagues that regulation of herbal products needs to be consistent with that applied to the pharmaceutical industry.
—H.C. George Wong, MD, FRCPC
Vancouver
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1. Perharic-Walton L, Murray V. Toxicity of traditional Chinese herbal remedies. Lancet 1992;346:674.
2. Kane JA, Kane SP, Jain S. Hepatitis induced by traditional Chinese herbs; possible toxic components. Gut 1995;36:146-147.
3. Wong HCG. Cardiac adverse reaction associated with Fu Zi: A case of mild aconite poisoning from Chinese herbal medicine. Ann R Coll Physicians Surg Can 2001;34:358-361.
4. Wong HCG. Natural health products, complementary and alternative medicine, and Health Canada. CMAJ 2017;189:E1268.