Principles of HRT

INDICATIONS for HORMONE REPLACEMENT THERAPY (H.R.T.)

• Relief of menopausal symptoms (short-term).
  
• Prevention / treatment of osteoporosis (long-term).
• Treatment of Early or Premature Menopause

CONTRAINDICATIONS for H.R.T.

• Pregnancy
• Undiagnosed abnormal vaginal bleeding
• Active thromboembolic disorder or acute-phase myocardial infarction
• Suspected or active breast or endometrial cancer
• Active liver disease with abnormal liver function tests
• Porphyria cutanea tarda

OTHER POSSIBLE BENEFITS

Reduction in risk of colonic cancer, macular degeneration and cataract formation, with improved dentition and skin healing. If commenced in the early menopausal years, possible reduction in cardiovascular disease and alzheimer type dementia-- these still controversial.

RISKS of H.R.T.

• Small increased risk of breast cancer with long-term treatment (> 5 years after age 50). Believed to be due to promotion of cancer cells rather than initiation.
  
• Small increased risk of venous thrombo-embolism with oral HRT, not transdermal - most significant in patients with other risk factors.
  
• Association between HRT and Cardiovascular disease.
  For many years, it was thought that HRT significantly reduced the risk of cardiovascular disease and stroke. Following studies such as the HERS and WHI studies, it appeared possible that certain types of HRT may confer an increased risk. It now seems that HRT commenced early in the menopause (within 10 years of the menopause, or under the age of 60) can provide benefit but if commenced later, when atherosclerosis is already present, there may be a small increased risk. More likely the cardiovascular benefit of starting early is not provided by late initiation of HRT. HRT should not currently be taken for presumed cardiovascular benefit, and HRT should only be prescribed to women who have cardiovascular disease if there are good indications, and after full discussion. In the presence of cardiovascular disease, transdermal estrogen, started in low dose, with progestin as required, is believed to be the safest route.

HORMONES INVOLVED

1. Estrogen - should be given continuously.
   
2. Progestogen - given in addition to estrogen in non-hysterectomised patients to reduce the risk of endometrial hyperplasia and endometrial cancer. Duration and frequency of the progestogen determines the presence and pattern of bleeding.

ROUTE of H.R.T.

1. Oral - Often first choice - cost-effective and acceptable.
   
2. Non-oral - Transdermal--patch or gel,  - have different metabolic effects e.g. on lipid metabolism and clotting system.
3. Non-oral therapies are thought to produce more physiological hormone levels than oral therapy, avoiding bolus first-pass effect on the liver.

INDICATIONS for NON-ORAL ROUTE

• Patient preference.
• Poor symptom control with oral treatment
• Side effects e.g. nausea with oral treatment.
• History of, or risk of venous thrombo-embolism (when HRT should only be considered after full discussion and appropriate investigation).
• BMI greater than 30, because of increased VTE risk.
• Variable hypertension (blood pressure should be controlled before starting HRT).
• Hypertriglyceridaemia.
• Current hepatic enzyme inducing agent, e.g. anticonvulsant therapy.
• Bowel disorder which may affect absorption of oral therapy.
• History of migraine (when steadier hormone levels may be beneficial).
• Lactose sensitivity.
• History of gallstones.

Wide range of types and routes of estrogen and progestogen allows flexibility and enables treatment to be individualised.