Editor—The incidence of obesity in the United Kingdom is increasing in parallel with an increase in the use of slimming aids, including traditional Chinese medicines. The safety and quality of herbal medicines have been weakly regulated because of an exemption in the Medicines Act 1968 that allowed them to be marketed without going through stringent criteria required for licensing of normal medicine.1
Between November 2003 and June 2004 we treated four patients who developed severe acute liver injury within two months of starting to take such a slimming aid (Shubao), widely available in the West Midlands. Three patients fully recovered on discontinuing the agent; one patient progressed to fulminant hepatic failure, requiring liver transplantation. Samples of Shubao were forwarded to the Medicines and Healthcare products Regulatory Agency (MHRA), and laboratory analysis showed adulteration with N-nitrosofenfluramine, a recognised hepatotoxin. This derivative of fenfluramine is an appetite suppressant that was withdrawn by the MHRA in 1997 after reports of cardiac valvar dysfunction.2 The N-nitroso derivative may have enhanced hepatotoxicity and has been linked with hepatic carcinogenesis.3
These patients highlight deficiencies in the previous regulation of the safety and quality of traditional Chinese medicines in the UK. The European Traditional Herbal Medicinal Products Directive, effective in the UK since October 2005, demands compulsory registration of all manufactured, prepackaged unlicensed herbal products, and represents progress in the regulation of manufactured herbal medicines.4 All new manufactured herbal medicines must meet specific standards of safety and quality, show either efficacy or longstanding traditional use, and be accompanied by the necessary information for the product to be used safely. All existing products must be compliant with the scheme by April 2011. This should ensure that all herbal medicines are of an acceptable standard and misleading claims are not made about efficacy.
Competing interests: None declared.
References
- 1.Medicines and Healthcare products Regulatory Agency. Directive 2004/24/EC: Full regulatory impact assessment: directive on traditional herbal medicinal products. www.mhra.gov.uk/home/groups/pl-p/documents/publication/con2022468.pdf (accessed 19 Jan 2006).
- 2.Connoly HM, Crary JL, McGoon MD, Hensrud DD, Edwards BS, Edwards WD, et al. Valvular heart disease associated with fenfluramine-phentermine. N Engl J Med 1997;337: 581-8. [DOI] [PubMed] [Google Scholar]
- 3.Hasegawa R, Futakuchi M, Mizoguchi Y, Yamaguchi T, Shirai T, Ito N, et al. Studies of initiation and promotion of carcinogenesis by N-nitroso compounds. Cancer Lett 1998;123: 185-91. [DOI] [PubMed] [Google Scholar]
- 4.The European Parliament and the Council of the European Union. Directive 2004/24/EC of the European Parliament and of the Council. Official Journal of the European Communities 2004;L136: 85-90. [Google Scholar]