January 14, 2009 — There is no strong evidence
either way for several herbal remedies commonly taken to relieve
troublesome menopausal symptoms, concludes the January issue of the
Drug and Therapeutics Bulletin (DTB). And for some, there is hardly any
evidence at all.
Between 30% and 70% of women in industrialised countries will
experience vasomotor symptoms around the menopause, such as hot flushes
and night sweats, prompted by the sharp fall in oestrogen levels.
On average, such symptoms last for around four years, but in around one in 10 women, they can last more than 12 years.
Herbal remedies commonly used to relieve menopausal symptoms include
black cohosh, red clover, Dong quai, evening primrose oil, and ginseng.
Others include wild yam extract, chaste tree, hops, sage leaf, and kava
But little good quality evidence on the effectiveness of herbal
medicines, or how they might react with prescription medicines is
available, says DTB.
And, in general, safety has been under researched, which is a major
concern given that herbal remedies are often assumed to be "safe" just
on the grounds that they are "natural," says DTB.
Published studies are often poorly designed, include too few participants, or don’t last long enough to be of real value.
Furthermore, the chemical make-up of various preparations of the
same herb may differ, which can make it difficult to compare trial
The drugs regulator, the Medicines and Healthcare products
Regulatory Agency (MHRA), has given a Traditional Herbal Registration
to Menoherb, which contains black cohosh, under a scheme designed to
boost the safety of herbal products on sale.
But clinical trial data on black cohosh are "equivocal," says DTB,
with some studies suggesting that the remedy works well, while others
suggest that it does not relieve symptoms effectively.
Liver toxicity is also a potential side effect of black cohosh.
There is "no convincing evidence" that red clover extract is
effective, says DTB, and little evidence one way or another for dong
quai, evening primrose oil, wild yam, chaste tree, hops, or sage.
This review appears in the new look DTB, which has been given its
first major design make-over since it was first published in 1962.
Pagination has also increased from eight to 12, in a "deliberate
attempt to address healthcare professionals’ needs for clear, succinct
information and practical advice on medicines, other treatments and the
overall management of disease," says an editorial, another new feature
of the redesign.
Other additions include the use of colour and a new layout, which
will allow for illustrations, to make DTB both even more informative
and more enjoyable to read.
Commenting on the move, DTB editor Dr Ike Iheanacho, said:
"For over 45 years, DTB has strived to produce rigorously researched
information and advice for healthcare professionals, to help ensure
patients get the best possible care. The newly redesigned version of
the publication aims to continue and build on this tradition."
Source : BMJ-British Medical Journal