Tibolone as Hormone Replacement Therapy
Tibolone is a synthetic steroid hormone used as an alternative to traditional hormone replacement therapy (HRT). It has oestrogenic, progestogenic, and androgenic properties. These combined actions help alleviate menopausal symptoms such as hot flushes, night sweats, mood changes, and vaginal dryness. It also helps prevent bone loss (osteoporosis) associated with menopause.
Tibolone’s metabolites target specific tissues:
- Oestrogenic effects: Mainly affect bones and the vaginal lining, reducing menopause symptoms and preventing bone loss.
- Progestogenic effects: Prevent endometrial hyperplasia (thickening of the womb lining).
- Androgenic effects: Can improve sexual function and libido.
How effective is Tibolone?
Vasomotor Symptoms
Tibolone is effective in managing hot flushes and night sweats, though studies show it is slightly less effective than traditional combined HRT. However, it generally causes fewer cases of unscheduled bleeding compared to combined HRT.
Bone Health
Tibolone helps prevent bone loss, similar to other HRTs. In the LIFT study, involving women aged 60-85 with osteoporosis, tibolone significantly reduced the risk of both vertebral and non-vertebral fractures.
Sexual Health
Tibolone may improve sexual function, particularly in women experiencing low libido during menopause. Its androgenic properties contribute to this effect, although evidence is mixed on whether tibolone is more beneficial for sexual health than other HRTs.
Who can use Tibolone?
Tibolone is suitable for post-menopausal women who have not had a natural period for at least one year. It can also be prescribed to women transitioning from cyclical or continuous combined HRT. It is not recommended for use before menopause, as it may cause irregular bleeding.
Tibolone has the same contraindications as combined HRT, including:
- Women with a history of breast cancer.
- Women with unexplained vaginal bleeding.
- Women with a history of blood clots or cardiovascular disease.
- Women with a history of breast cancer or at high risk of breast cancer.
- Women over 60 should use tibolone with caution due to an increased risk of stroke.
- Women with a history of cardiovascular disease, blood clots, or liver disease.
Long-term safety of Tibolone
Breast Health
Preclinical studies suggest tibolone may reduce breast cancer risk by affecting oestrogen metabolism. However, the LIBERATE study showed an increased risk of breast cancer recurrence in women with a history of the disease. Therefore, tibolone is not recommended for women with a history of breast cancer. In women without a history of breast cancer, research is inconclusive, with some studies reporting no increased risk and others, like the Million Women Study, showing a slight increase in breast cancer risk.
Stroke Risk
Tibolone may increase the risk of stroke, particularly in women over 60. The LIFT study found that women aged 60-69 taking tibolone were 2.8 times more likely to experience a stroke compared to those taking a placebo. Caution is advised when prescribing tibolone to older women.
Cardiovascular Disease and Lipids
Limited research suggests that tibolone does not significantly increase the risk of cardiovascular events, such as heart attacks or strokes, compared to other HRTs. Some studies have shown that tibolone reduces total cholesterol and triglycerides, but its overall effects on heart health remain uncertain.
Endometrial Cancer
There is some evidence of a possible increased risk of endometrial cancer in tibolone users, though this has not been consistently shown in clinical trials. Women experiencing unexpected vaginal bleeding while taking tibolone should seek medical advice for further investigation.
Tibolone is an effective option for managing menopausal symptoms and preventing bone loss. It can be an alternative to conventional HRT for women who wish to improve sexual function. However, it is not recommended for women with a history of breast cancer and should be used cautiously in women over 60 due to the increased risk of stroke.
If you are considering tibolone, speak with your healthcare provider to determine if it is the right treatment for you, taking into account your personal medical history and risk factors.
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