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Herbal medicines in the management of menopausal symptoms

In the first of two articles, Alyson Huntley describes the risks and benefits of the unregulated alternatives to hormone treatment that many women use to self-medicate

In the first of two articles, Alyson Huntley describes the risks and benefits of the unregulated alternatives to hormone treatment that many women use to self-medicate

Women who self-medicate with herbal over-the-counter medicines for menopausal symptoms can be a complicated problem for GPs. How safe and effective are these poorly regulated but widely used treatments? What happens if a woman does seek advice from their GP? How is it possible to advise on an area of medicine with such little regulation and control?

Herbal medicines for menopause symptoms are extremely popular, especially for hot flushes. Even before the recent controversies with HRT, surveys suggested that the most common reason for seeking alternative treatments during the menopause was a perceived risk of side-effects with HRT. One of the most popular choices is evening primrose oil, which is not really a herbal medicine but a 'nutritional supplement'. However, it is important to include as it is widely used. There is no evidence to suggest it is effective for vasomotor symptoms and indeed no sensible rationale for a mechanism of action. The one small trial that has investigated evening primrose for hot flushes showed no difference in effect above that of the placebo. However, no serious adverse effects of evening primrose oil are known.

Black cohosh is the most well-known herbal medicine for menopausal symptoms, but only recently have higher quality clinical trials been performed. A recent system-atic review of randomised controlled trials (RCTs) failed to find evidence for the clinical effectiveness of black cohosh at a dose of 40mg. More important is the safety of this herb considering its popularity. There are no known drug-herb interactions with the use of black cohosh and the adverse events reported in clinical trials are mild, transient and probably non-specific. It is also important to note that black cohosh extracts contain nothing with any oestrogenic activity, and its mechanism is unclear. However, a number of recent case reports have linked black cohosh with acute liver disease. With the evidence available and the lack of a plausible mechanism of hepatoxicity, it is impossible to make a definitive statement.

The MHRA has made recommendations in response to these reports(see table below). St John's wort is well known for its benefit in mild to moderate depression, but it is known to have significant interactions with conventional drugs. One uncontrolled study (900mg daily for three months) showed a positive effect on psychological symptoms of the menopause.

Kava is of interest, although not for the right reasons. It has a good evidence base as an anxiolytic agent and has been the subject of at least two clinical trials for menopausal symptoms. Unfortunately it has also been linked to hepatoxicity, and in 2003 was removed from the UK market. Regrettably, it can still be readily obtained over the internet and by mail order.

Multi-herbal preparations

Herbal products are often combined when used as treatments for the menopause. There is generally no research either for the individual herb or the combination and they are put together on the basis that they are traditionally considered 'women's herbals' with natural oestrogenic properties.

Black cohosh has been combined with St John's wort as a treatment for both the psychological and physiological symptoms of the menopause. Two double-blind, placebo-controlled RCTs (n=301, n=89 respectively) have shown this combination to be of benefit for the menopause in terms of both climacteric and psychological symptoms (with the more recent study also suggesting a positive effect on lipid metabolism). It is unclear whether both studies used the same dosage, however the largest and longer trial used a dosing regime of two tablets orally twice daily for weeks one to eight, and one tablet twice per day for weeks nine to 16 (each tablet containing a standardised 1.0mg triterpene glycosides of black cohosh extract and 0.25mg hypericine of St John's wort extract).

One of the major problems regarding the safety of herbal medicines in the UK is regulation. The situation is being improved with the re-evaluation of herbal product registration and licensing, and the introduction of a traditional use licence. But there is still a lack of information on exact usage and safety, making it important for GPs to be aware of the risks of their use.

MHRA recommendations on use of black cohosh

•Warnings regarding rare adverse reactions in the liver should be added to the product information for black cohosh for both licensed and unlicensed products

•The issue of liver toxicity with black cohosh should be monitored closely and further information should be gathered on the composition and quality of black cohosh products available in the UK

•Licence holders of black cohosh products should study the potential mechanism by which black cohosh is associated with liver injury

Key points

Herbal medicines with some evidence of benefit

•Black cohosh (Cimicifuga/Actaea racemosa)

•St John's wort (Hypericum perforatum)

•Black cohosh-St John's wort combination

Popular herbal medicines with little or no evidence of benefit

•Burdock (Arctium lappa) •Chastetree (Vitex agnus castus)

•Hops (Humulus lupulus) •Dong quai (Angelica sinensis)

•Evening primrose oil (Oenothera biennis) •Flax seed (Linum usitatissimum)

•Geranium (Pelargonium graveolens) •Ginkgo (Ginkgo biloba)

•Ginseng (Panax ginseng) •Valerian (Valariana officinalis)

•Liquorice root (Glycyrrhiza glabra) •Motherwort (Leonurus cardiaca)

•Sage (Salvia officinalis) •Lemon balm (Melissa officinalis)

•Wild yam (Dioscorea villosa) •Red clover (Trifolium pratense)

Herbal medicines to be avoided

•Kava (Piper methysticum)

There is little or no evidence of benefit for most popular herbs in menopausal women There is little or no evidence of benefit for most popular herbs in menopausal women

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