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From a medical perspective, the menopause presents two potential problems. First, about a third of women will have significant symptoms, such as severe flushes often associated with insomnia, muscle aches and pains, formication, fatigue, palpitations and mood swings. Second are the long term issues, in particular the prevention and treatment of osteoporosis. Unfortunately, the first symptom of osteoporosis is fracture, and over the past decade medical research has taught us that clinical trials focusing on surrogate endpoints such as bone density are not good enough. The gold standard clinical bone trial measures fractures as the primary endpoint. However, these studies are very expensive (typically around US$500 million), and are well beyond the budget of most herbal or supplement companies. Thus, herbal medicines may have a short term role in managing the symptoms of menopause, rather than treating the long term aspects. For most women the acute symptoms of menopause last 1-3 years and then disappear, although around 10% of women have persistent flushes. Around half will have symptomatic vaginal atrophy requiring topical oestrogens, vaginal moisturisers or lubricants.

What is the evidence that these herbal medicines are efficacious and safe? The findings by Davis and colleagues in this issue of the Journal add to the body of knowledge on herbal medicines and menopause.² Their carefully constructed double-blind randomised placebo-controlled trial, which took great care in designing a placebo, found no evidence of efficacy. Over 12 weeks there was a large placebo effect (of approximately one third) and no significant difference between the placebo and the herbal preparation.

The safety of Chinese herbal medicines has come under recent scrutiny. Aristolochia fangchi is a Chinese herb that can cause a progressive form of renal fibrosis and renal failure, and recently it has been reported that 46% of those affected by aristolochia nephropathy also had uroepithelial carcinoma.³ This herb has no therapeutic value, but is sometimes inadvertently replaced for other herbs such as stephania or magnolia. The Therapeutic Goods Administration recently banned aristolochia, but importers of Chinese herbal medicines may not be aware that their product has been contaminated by aristolochia. Clearly, some form of testing needs to be instituted. It is also apparent that some herbal therapies have undesirable hormonal effects. A popular, commercially available combination of eight herbal medicines used to treat prostate disease in the United States was found to have potent oestrogenic activity.⁴ Finally, some herbals may interact with medical treatments, the best known example being St John's wort, which inhibits monoamine oxidase activity,⁵ and so can potentiate the effect of pharmacological antidepressants.

The efficacy and safety of phytoestrogens was recently reviewed by the North American Menopause Society and the data published as a consensus opinion.⁶ In essence, it seems that phytoestrogens are largely safe, although safety has not yet been established among particular subgroups of patients (eg, women who have had breast cancer). Basic science studies have shown that these compounds have some effect on the cardiovascular system, improving elasticity and compliance of large vessels and perhaps some effect on the lipoprotein profile; however, the body of evidence at the moment suggests that phytoestrogens have little, if any, beneficial effect on bone metabolism, and, if there is an effect on menopausal symptoms, it is mild and not much greater than that of placebo. In a double-blind randomised controlled trial using dong quai for treating menopausal symptoms,⁷ no therapeutic effect was found and no oestrogenic effect on the endometrial thickness or on vaginal epithelium was demonstrated. Similarly negative trials are available for evening primrose oil⁸ and wild yam cream.⁹ At present, the most promising candidate for an effective herbal medicine for treating menopausal symptoms is an extract of black cohosh, Remifemin (Scinat, Australia), which has been subjected to two clinical trials.^10,11 Both trials showed a significant effect on menopausal symptoms compared with a placebo (typically, a 60% to 70% improvement over 12 weeks), with no oestrogenic effect on vaginal epithelium, endocrine hormone levels, or endometrial thickness. Interestingly, in Germany, extract of black cohosh is commonly combined with St John's wort for the treatment of menopausal symptoms.

Thus, currently available evidence indicates that most of the herbal products that our patients take for menopausal symptoms are ineffective, and some have serious questions concerning safety. Davis and colleagues are to be congratulated for conducting a quality double-blind randomised trial that adds to our knowledge on herbal medicines and menopause. Doctors should make use of this knowledge base, and be proactive in providing accurate information about both HRT and herbal medicines (Box) to women seeking relief for their menopausal symptoms.

John A Eden
Associate Professor, Reproductive Endocrinology
School of Obstetrics and Gynaecology, Faculty of Medicine
University of New South Wales, Sydney, NSW

1. Collaborative group on hormone factors in breast cancer. Breast cancer and hormone replacement therapy: collaborative re-analysis of data from 51 epidemiological studies of 5,705 women with breast cancer and 108,411 women without breast cancer. Lancet 1997; 350: 1047-1059.
2. Davis SR, Briganti EM, Chen RQ, et al. The effects of Chinese medicinal herbs on postmenopausal vasomotor symptoms of Australian women. A randomised controlled trial. Med J Aust 2001; 174: 68-71.
3. Nortier JL, Martinez MCM, Schmeiser HH, et al. Urothelial carcinoma associated with the use of a Chinese herb (Aristolochia fangchi). N Engl J Med 2000; 342: 1686-1692.
4. Di Paola RS, Shang H, Lambert GH, et al. Clinical and biological activity of an estrogenic herbal combination (PC-SPES) in prostate cancer. N Engl J Med 1998; 339: 785-791.
5. Cott JM. In vitro receptor binding and enzyme inhibition by Hypericum perforatum extract. Pharmacopsychiatry 1997; 30 Suppl 2: 108-112.
6. The role of isoflavones in menopausal health: Consensus opinion of the North American Menopause Society. Menopause 2000; 7: 215-229.
7. Hirata JD, Swiersz LM, Zell B, et al. Does Dong Quai have estrogenic effects in postmenopausal women? A double blind placebo controlled trial. Fertil Steril 1997; 68: 981-986.
8. Chenoy R, Hussain S, Tayob Y, et al. Effective oral gamolenic acid from evening primrose oil on menopausal flushing. BMJ 1994; 308: 501-503.
9. Komesaroff PA, Black CVS, Cable V. Effects of wild yam extract on menopausal symptoms and hormonal and biochemical parameters [abstract]. Australasian Menopause Congress, Auckland, October 1998.
10. Eden JA, Mackey R, McFarland K, et al. A pilot study of Remifemin for menopausal symptoms [abstract]. Australasian Menopause Society Congress, October 1997, abstract book: 97.
11. Stoll W. Phytopharmacon influences atrophic vaginal epithelium: double blind study -- cimifuga vs estrogenic substances. Therapeuticon 1987: 1; 23-31.

©MJA 2001
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