Hormone Replacement Therapy
There is an increased
risk of endometrial cancer. This risk can be reduced by use of a progestogen,
however the use of a progestogen decreases risk reduction in stroke and MI.
The increased risk of
breast cancer is related to the duration of HRT. Within about 5 years of
stopping HRT the excess risk of breast cancer disappears. Women who use HRT for
a short time around the menopause have a very low excess risk.
It is advised that women
without predisposing factors for thromboembolism can continue
HRT without excessive risk. In women with predisposing factors the
balance of the benefits of HRT need to be weighed against the risk of
The Vaginal atrophy for which HRT is
prescribed can also be treated with vaginal oestrogen preparations for a few
weeks (can be repeated if necessary) thereby avoiding the increased risks of
endometrial and breast cancer and risks of venous thromboembolism. The Vaginal
preparations, however, cannot alter systemic vasomotor effects of the menopause.
Oestrogen-dependent cancer, active thrombophlebitis or thromboembolic disorders,
liver disease, undiagnosed vaginal bleeding, breast feeding
Migraine, history of
breast nodules, fibrocystic disease, pre-existing uterine fibroids,
endometriosis, risk factors for thromboembolic disease, porphyria
Nausea and vomiting,
abdominal cramps and bloating, weight changes, breast enlargement and
tenderness, premenstrual-like syndrome, sodium and fluid retention, changes in
liver function, changes in libido, depression, headache, migraine and dizziness.
Natural oestrogens (oestradiol,
oestrone, and oestriol) and conjugated oestrogens are appropriate for use in
hormone replacement. Oestrogen
therapy can be given continuously or cyclically.
Progestogen is also
necessary if the patient has a uterus (eg: has not had a hysterectomy ) or is
not on a combined therapy such as tibolone.
Oral preparations of
oestrogens are subject to first pass metabolism. Subcutaneous and transdermal administration more closely
mimic endogenous hormone activity. However,
subcutaneous implants can cause rebound vasomotor symptoms reflecting
supraphysiological plasma concentrations. Prolonged
endometrial stimulation occurs even after discontinuation and should be
considered (as with all hormone replacement therapies) in the event of surgery
which is an additional risk actor for venous thromboembolism.
Women with Uterus:
Therapies must include a progestogen.
The addition of a progestogen is essential to minimize the risk of cystic
hyperplasia of the endometrium, which can lead to cancer.
Unfortunately, the addition of progestogen diminishes the benefits of
oestrogens on MI and stroke risk.
Cyclical HRT involves progestogen taken for 10-14 days of each 28 day
oestrogen cycle treatment. There is usually a resultant withdrawal bleed towards
the end of the progestogen. Continuous combined HRT aims to avoid bleeding.
Irregular bleeding can still occur in the beginning of treatment. Some examples
are: Prempak-C, Climagest.
These preparations do not include progestogens.
Treatments can be in tablet form e.g: Premarin, harmogen; implants (Estradiol
implants); patches (Menorest, FemSeven) or
as gels (Oestrogel)
Tibolone is a slight exception to the above categories. It is an
oestrogen and progestogen combined pill with weak androgenic activity. It is
given continuously (with no need for additional progestogen.)