Use of herbal medicines

Current situation

  • Legally, herbal products are classified as food supplements and are widely available from health food shops and chemists.
  • In the UK, around 30 per cent of adults have tried herbal medicines.
  • Worldwide several thousand different plants are being used for medicinal purposes.

What is the evidence?

  • For most herbal treatments good trials of efficacy are lacking, and conducting them would be expensive.
  • Without evidence of efficacy, it is hard to judge the safety of herbal medicines, not least because the risk of an adverse effect that might be acceptable for an effective treatment will be unacceptable for an ineffective one (BMJ 2005; 331: 62–3).
  • Saw palmetto has shown no benefit over placebo for the symptoms of benign prostatic hyperplasia, according to a double blind, randomised trial — despite over two million men in the US taking it.(NEJM 2006; 354: 557–66).
  • The widely used herbal remedy black cohosh, alone or combined with other botanical agents, does not seem to relieve the vasomotor symptoms of menopause better then placebo (Ann Intern Med 2006; 145: 869–79).
  • A systematic review found that there is no compelling evidence of the efficacy of any herbal medicine for COPD, although herbal medicine is popular among patients with COPD (Eur Respir J 2006; 28: 330–8).
  • Hawthorn extract can lower BP in hypertensive diabetic patients, which can be beneficial; in this study, patients taking hawthorn experienced a significant 2.6mmHg reduction in diastolic BP (BJGP 2006; 56: 437–43).

Implications for practice

  • Many patients still believe that doctors prescribe too many medicines. Some also suspect that medicines are either addictive or lose some of the efficacy with regular use.
  • Patients fear the safety of medicines. They perceive treatments containing herbal agents to be ‘natural’ and therefore safe.

Available guidelines

  • In the UK, the Medicines and Healthcare products Regulatory Agency (MHRA) is introducing a Herbal Medicines Advisory Committee, which will advise on issues relating to registration of traditional herbal medicinal products.
  • The European Traditional Herbal Medicinal Products Directive demands compulsory registration of all manufactured, prepackaged unlicensed herbal products.

All new manufactured herbal medicines are required to meet specific standards of safety and quality, and they should show either efficacy or long-standing traditional use, and must be accompanied by the necessary information for the product to be used safely.

Useful websites

www.mhra.gov.uk — MHRA

Dr Louise Newson is a GP in the West Midlands and author of ‘Hot Topics for MRCGP and General Practitioners’ PasTest 2006

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