Focus on Alternative and Complementary Therapies
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Focus Alternat Complement Ther©2005 Pharmaceutical Press
Around 200 delegates from over 30 countries attended this 2-day symposium which marked ESCOP’s 10th anniversary and the launch of an online newsletter The European Phytojournal. Regulatory perspectives on herbal medicinal products (HMPs) and safety issues were major areas covered.
Dr Rolf Bass (European Agency for the Evaluation of Medicinal Products (EMEA)) said that the main route for bringing HMPs to the European market was the mutual recognition procedure. However, to date, only three HMPs—sesame oil, ispaghula husk and valerian root—had been assessed in this way. “The procedure is not yet perfect and amenable to the larger number of herbal medicinal products … there is certainly room for improvement”, Dr Bass commented.
The main problems are major differences in the assessment of quality, safety and efficacy between member states, the complexity of herbal drug preparations, and the interpretation of bibliographic data. Better guidance is needed, he said. In an effort to meet this need, the EMEA ad hoc Working Group on Herbal Medicinal Products (HMPWG) was created in May 1997.
Dr Konstantin Keller (Chairman, ad hoc HMPWG) said the group’s overall aim is to facilitate the approach of HMPs to a common European market by eliminating obstacles to mutual recognition. According to Dr Keller, the HMPWG has concentrated its work on ready-prepared HMPs (rather than crude botanical drugs) as major differences in the assessment of quality, safety and efficacy of these products may represent a risk for consumers.
On fixed combination products, a characteristic aspect of phytotherapy, Dr Keller said, “irrational fixed combinations will not have a chance to exist on the European market”. He said that it must be demonstrated that each individual component contributes to the overall efficacy of the product.
Mr ROY ALDER (Medicines Control Agency (MCA)) remarked that herbal medicine could be at some risk from its own success. He emphasised, “all those who wish to secure the long-term future of herbal medicines must aspire to the highest scientific standards”. He went on to say “there is now a steady trickle of evidence that some herbal products are not of sufficient quality”. He described the contamination of eczema creams with conventional (prescription-only) drugs as a recent example of this. “The MCA has taken enforcement action and will continue to do so as necessary”, he warned. Other MCA initiatives included:
Mr Alder also drew attention to initiatives undertaken by other organisations, such as the British Herbal Medicine Association’s (BHMA) code of good practice on unlicensed herbal remedies which includes the requirement that its members adhere to GMP for such products, and the development of an authentication centre for Chinese herbal material at the Royal Botanic Gardens at Kew.
Looking to the future, Mr Alder said, “we are clearly reaching a crossroads … important decisions will have to be made [on the future regulation of HMPs]”. He called for “maturity and sensitivity” in the inevitable wide-ranging debate, saying, “The challenge is to get the regulatory balance right”, he said.
As for conventional drugs, safety and toxicity data on herbal medicines are collected from all over the world by the World Health Organisation (WHO) Collaborating Centre for International Drug Monitoring. Professor RALPH EDWARDS (director of the centre) said that the centre had received a total of 8986 reports of adverse reactions where products with one or more herbal ingredients were suspected.
Although the total number of herbal ADR reports has increased since 1994 (when there 4960 reports in total), it represents only a small proportion of the 1.8 billion ADR reports held on the WHO database. Professor Edwards questioned whether this was because herbals were safe, or whether it was a consequence of gross under-reporting of herbal ADRs. “It is recognised that herbals appear to be less frequently associated with ADRs than most pharmaceuticals, but they [herbal products] still give us cause for concern”, he said. A major problem in herbal ADR reporting is the confusion over terminology with regard to herbal nomenclature, explained Professor Edwards. He used “ginseng” and “scullcap” as examples of herbals for which confusion over terminology can arise. The WHO is tackling the problem by developing a better classification system for plants, plant parts, plant extracts and the content of herbal products, and has an ongoing collaboration with the Royal Botanic Gardens at Kew, London, UK.
Professor DAVID PHILLIPSON (emeritus professor of pharmacognosy, School of Pharmacy, University of London) said that although there were relatively few reports in the literature of drug interactions involving herbal products, there is a potential for such interactions to occur. Herbal products may potentiate or antagonise effective drug treatment, or may enhance the toxicity of pharmaceuticals, he continued. Therefore, drug-herb interactions should be systematically evaluated, he said. Professor Phillipson went on to give several examples where there was a “theoretical possibility” that interactions between conventional drugs and herbal products could occur.
J Barnes, Exeter, UK