When a women stops menstruating for more than 12 months she is said to have attained menopause. Menopause could be natural or surgically induced when the ovaries are removed. The period preceding menopause is called the perimenopausal period where women experience a variety of vasomotor and psychological symptoms. Depression, hot flashes, mood swings, vaginal dryness, insomnia etc are some of the common complaints by women in the menopausal age group.
Symptoms of menopause could be a cause of severe morbidity in some women requiring therapy. Research has also shown that women in this age may be prone to an increased risk of developing cardiovascular incidents and osteoporosis. A simple alternative then would be to replace the protective female hormones. This leads to the prescription of hormone replacement therapy (HRT) in menopausal women.
Hormone replacement therapy has bought relief many women from symptoms like insomnia, depression and hot flashes. Despite this, there is an alarming correlation between HRT and development of breast cancer which has kept women away from HRT. Also, some women may be reluctant to take exogenous estrogens and hence never seek treatment. Scientists are hence on the look out for some natural compounds that can be used to safely to treat menopausal symptoms in women.
Black Cohosh is a perennial woodland herb also called as Actaea racemosa L. It is widely distributed in North America where its roots have been used for treatment of cough, cold, constipation, fatigue and rheumatism. In the nineteenth century, black cohosh was used for treatment of endometriosis and dysmenorrhoea. Its use for gynecological problems continues even now as it is marketed as a supplement for the treatment of menopausal symptoms.
Mechanism of action:
Its mechanism of action is not very clear and may have some estrogen receptor mediated effect. Clinical trials have given contradictory results and recent trials refute the possibility of receptor mediated activity of black cohosh. Dopaminergic and serotonergic effects have been proposed more recently.
Black cohosh extracts made from its roots are marketed commercially. Remifemin is the only standardized preparation available which has been tested clinically for its safety and efficacy. It can be consumed in the dose of 40 to 80 mg per day. The treatment must be taken for a period of 4 to 12 weeks for the benefits to be apparent.
Ingestion of black cohosh has lead to side effects like nausea, headaches, weight gain, mastalgia and dizziness. These appear to be side effects due to its action on the female sex hormones. For the same reason, black cohosh must be avoided in pregnant and lactating women and also children.
Animal studies on the mechanism of action of black cohosh have been inconclusive. Similarly clinical trials performed to determine its utility on the treatment of menopausal symptoms have been disappointing. Large scale randomized double blinded clinical trials must be carried out with appropriate controls to scientifically prove the efficacy of black cohosh as a safe and effective herb in the treatment of menopausal symptoms.
Gail B. Mahady, Daniel Fabricant, Lucas R Chadwick, Birgit Dietz Black Cohosh: An Alternative Therapy for Menopause? Nutr Clin Care. 2002; 5: 283- 289