Premarin

Indications

Conjugated Estrogens are a mixture of estrogen hormones used for hormone replacement therapy (HRT) to relieve moderate to severe menopausal symptoms such as hot flushes, night sweats and vaginal dryness, and to help prevent osteoporosis after menopause in women at high risk when other treatments are not suitable. They are also used for low estrogen levels due to underactive ovaries or removal of the ovaries, and occasionally for abnormal uterine bleeding caused by hormone imbalance or for some advanced cancers, as decided by a specialist. Vaginal cream forms are used for vaginal dryness and irritation after menopause.

How It Works

Estrogen is a female hormone made by the ovaries. After menopause, levels fall, which causes hot flushes, vaginal dryness and faster bone loss. Conjugated estrogens replace some of this hormone, easing symptoms, keeping the vaginal lining healthier and slowing bone loss.

Dosage and Administration

The dose and form (tablets or vaginal cream) are decided by your doctor, as prescribed, using the lowest effective dose for the shortest time needed. Tablets are usually taken once a day at the same time. Women who still have a womb (uterus) are normally also given a progestogen to protect the womb lining from cancer. Review treatment with your doctor at least once a year.

Interactions

• Rifampicin, Carbamazepine, Phenytoin, Phenobarbital and St John's Wort may reduce its effect.
• Ketoconazole, Itraconazole, Clarithromycin and grapefruit juice may increase estrogen levels.
• It may change the effect of Warfarin, thyroid hormone (Levothyroxine dose may need increasing), diabetes medicines and Lamotrigine.

Contraindications

• Known, suspected or past breast cancer, or other estrogen dependent cancer such as endometrial cancer.
• Undiagnosed vaginal bleeding.
• Untreated thickening of the womb lining (endometrial hyperplasia).
• Current or past blood clots in the legs or lungs, or a known clotting disorder.
• Recent or current heart attack, angina or stroke.
• Active or past serious liver disease with abnormal liver tests, and porphyria.
• Pregnancy, and allergy to the medicine.

Side Effects

Common effects include breast tenderness or enlargement, nausea, bloating, headache, leg cramps, vaginal bleeding or spotting, fluid retention, mood changes and weight changes. Long term use is linked with a higher risk of blood clots, stroke, gallbladder disease, breast cancer and, without a progestogen, cancer of the womb lining.

Get urgent medical help if you have pain or swelling in one leg, sudden chest pain or breathlessness, a sudden severe headache, weakness or numbness of one side of the body, difficulty speaking, sudden vision changes, yellowing of the skin or eyes, a new breast lump, or unexpected heavy vaginal bleeding.

Pregnancy and Lactation

Must not be used in pregnancy. If pregnancy occurs, stop and see a doctor. Not recommended during breastfeeding, as it may reduce milk supply and pass into milk.

Precautions and Warnings

• Have regular breast checks and screening, and report any breast or vaginal changes.
• Use with care if you have high blood pressure, diabetes, migraine, epilepsy, asthma, endometriosis, fibroids, gallstones, lupus or a family history of clots or breast cancer.
• Stop before major planned surgery or long immobility if your doctor advises, because of clot risk.
• Estrogen therapy should not be used to prevent heart disease or dementia.

Overdose

Overdose may cause nausea, vomiting, breast tenderness, drowsiness and vaginal bleeding. Serious effects are unlikely; contact a doctor for advice.

Therapeutic Class

Estrogen hormone (hormone replacement therapy).

Storage

Store below 30°C in a dry place, away from light and out of the reach of children.