Drugs that act in a similar way to female sex hormones and that are used to reduce symptoms associated with the menopause
At the menopause, there is a decline in the levels of the sex hormone oestrogen. Hormone replacement therapy (HRT) can be used to restore oestrogen to pre-menopausal levels. Reduced oestrogen levels may lead to symptoms such as hot flushes and vaginal dryness. In the long term, low levels of oestrogen may increase the risk of osteoporosis and heart disease. Menopausal symptoms may be particularly severe after surgical removal of the ovaries or following radiotherapy of the pelvic area in the treatment of cancer. Whether they occur naturally or after surgery or radiotherapy, the symptoms of the menopause are usually relieved by HRT.
HRT usually consists of a combination of oestrogen and a progestogen (a synthetic form of the hormone progesterone). Oestrogen that is taken alone is associated with a higher than normal risk of cancer of the uterus. For this reason, most women are also prescribed a progestogen, which gives protection against uterine cancer. In the case of women who have had a hysterectomy, usually oestrogen alone is prescribed. Tibolone combines the action of both oestrogen and progestogen in a single preparation.
How is it used?
HRT is usually given in the form of tablets, skin patches, or as a combination of the two. Tablets are taken daily; patches are usually changed twice a week and should be placed on a different area of skin each time. Other forms of HRT include a gel that is rubbed into the skin daily and a vaginal ring impregnated with oestrogen. Oestrogen creams, applied to the vagina for several weeks to treat vaginal dryness, may also be used. Courses of treatment with creams can be repeated if necessary, but the smallest effective dose should be used to minimize possible effects on other parts of the body.
In women with a uterus, HRT involves taking a continuous dose of an oestrogen, which is combined with a progesterone for 10 to 13 days of the 28-day cycle. The progesterone causes bleeding similar to that of menstruation, which is necessary to prevent excessive thickening of the lining of the uterus and the risk of it becoming cancerous. Alternatively, when more than a year has passed since the last menstrual period, continuous, bleed-free HRT or a single drug with both oestrogenic and progestogenic effects (such as tibolone) may be used. Women who have had a hysterectomy need only take oestrogen drugs.
HRT does not provide contraception, and you should consult your doctor about how long contraception should be used and the type most suitable for you.
Whether or not treatment with HRT is appropriate is a complicated issue and varies according to the particular woman concerned. For this reason, it is important to discuss with your doctor the risks and benefits of HRT that may apply in your specific case. However, in general, HRT is usually only advised for short-term use around the menopause to treat symptoms such as hot flushes and vaginal dryness. In addition, it is advised that the minimum effective dose of HRT is used for the shortest duration. HRT is no longer recommended for long-term use for the relief of menopausal symptoms nor for the treatment of osteoporosis because of the increased risk of disorders such as breast cancer, stroke, and thromboembolism (see Thrombosis and embolism). There may also be an increased risk of coronary artery disease in women who start HRT more than 10 years after the menopause. The increased risk of breast cancer is related to duration of HRT use; the risk reduces to its previous level within about 5 years of stopping HRT.
What are the side effects?
If you are taking oestrogen, you may experience some side effects. These include nausea, headaches, and mood swings. Oestrogen may also cause breast tenderness, fluid retention, fluctuating weight, and eye irritation when wearing contact lenses. Progestogens can produce similar side effects to oestrogen, and occasionally cause acne and skin rashes. Such side effects are usually temporary and disappear after 1–2 months of treatment.
From the 2010 revision of the Complete Home Medical Guide © Dorling Kindersley Limited.
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