Premarin tablets contain conjugated oestrogens as the active ingredient. These are a naturally-occuring form of the main female sex hormone, oestrogen.

What is Premarin used for?

  • Hormone replacement therapy to relieve symptoms of the menopause.
  • Premarin tablets are a continuous, oestrogen-only form of HRT. As they only contain oestrogen, they are most suitable for women who have had a hysterectomy. Women who have not had a hysterectomy should also be prescribed a progestogen medicine to take with this medicine for the last 12 to 14 days of each 28-day pack. This is because oestrogen stimulates the growth of the womb lining (endometrium), which can lead to endometrial cancer if the growth is unopposed. A progestogen is given to cause a monthly withdrawal bleed, which opposes oestrogen's effect on the womb lining. This reduces the risk of endometrial cancer, though it does not eliminate this risk entirely. This is known as combined HRT.
If a woman has had her womb surgically removed (a hysterectomy), endometrial cancer is not a risk, and a progestogen is not necessary as part of HRT (unless the woman has a history of endometriosis).
  • Second-line option for preventing osteoporosis in postmenopausal women who are at high risk of fractures and cannot take other medicines licensed for preventing osteoporosis.
  • In December 2003, a review of the available evidence on the risks and benefits of HRT by the Medicines and Healthcare products Regulatory Agency (MHRA) and the Committee on Safety of Medicines (CSM) in the UK, concluded that the risks of using HRT long-term to prevent osteoporosis in women aged over 50 years exceed the benefits. As a result, this medicine should not be used as a first-line option for preventing postmenopausal osteoporosis in women over 50. However, it may be used as a second-line option for women at high risk of fractures who cannot take other medicines that are licensed for this purpose.
  • Women considered to be at risk of developing fractures following the menopause include those who have had an early menopause, those with a family history of osteoporosis, those who have had recent prolonged corticosteroid therapy (eg prednisolone), those with a small thin frame, and smokers.
  • You can read more about the risks and benefits of HRT and other medicines for preventing osteoporosis in the factsheets about menopause and osteoporosis linked above.
  • How does Premarin work?

    • Premarin tablets contain conjugated oestrogens as the active ingredient. These are a naturally-occuring form of the main female sex hormone, oestrogen.
    • Womens'' ovaries gradually produce less and less oestrogen in the period up to the menopause, and oestrogen blood levels decline as a result. The declining levels of oestrogen can cause distressing symptoms, such as irregular periods, hot flushes, night sweats, mood swings and vaginal dryness or itching.
    • Oestrogen (in this case in the form of conjugated oestrogens) can be given as a supplement to replace the falling levels in the body and help reduce these distressing symptoms of the menopause. This is known as hormone replacement therapy (HRT). HRT is usually only required for short-term relief from menopausal symptoms and its use should be reviewed at least once a year with your doctor.
    • HRT is also sometimes used to prevent osteoporosis in postmenopausal women. The declining level of oestrogen at menopause can affect the bones, causing them to become thinner and more prone to breaking. Oestrogen supplements help prevent bone loss and fractures that may occur in women in the years after menopause.

    How do I take Premarin tablets?

    • Premarin tablets should be taken once a day on a continuous basis. Your need for continued HRT should be reviewed with your doctor at least once a year.
    • The tablets should be swallowed whole with a drink. They can be taken either with or without food.
    • Your tablet should be taken at around the same time each day; this will help you remember to take it.
    • If you forget to take a dose you should take it as soon as you remember, unless it is nearly time for your next dose. In this case just leave out the forgotten dose and take your next dose as usual at your usual time. Don't take a double dose to make up for a missed dose.

    Premarin should be used with caution by

    • Women with a risk of developing cancers that are stimulated by oestrogen, for example women whose mother or sister has had breast cancer.
    • Women with a history of benign breast lumps (fibrocystic breast disease).
    • Women with fibroids in the womb.
    • Women with a history of endometriosis.
    • Women with a history of overgrowth of the lining of the womb (endometrial hyperplasia).
    • Women with a personal or family history of blood clots in the veins (venous thromboembolism, eg deep vein thrombosis or pulmonary embolism).
    • Women taking medicines to prevent blood clots (anticoagulants), eg warfarin.
    • Women who are very overweight or obese.
    • Women with severe varicose veins.
    • Smokers.
    • Women with high blood pressure.
    • Women with diabetes.
    • Women with raised levels of fats such as cholesterol or triglycerides in their blood.
    • Women with a history of gallbladder disease.
    • Women with a long-term condition called systemic lupus erythematosus (SLE).
    • Women who suffer from migraines or severe headaches.
    • Women with inherited blood disorders called porphyrias.
    • Women with a history of irregular brown patches appearing on the skin, usually of the face, during pregnancy or previous use of hormone preparations such as contraceptive pills (chloasma). Women with a tendency to this condition should minimise their exposure to the sun or UV light while taking HRT.

    Premarin should not be used by

    • Women with known, suspected, or a past history of breast cancer.
    • Women with known or suspected cancer in which growth of the cancer is stimulated by oestrogen, eg cancer of the lining of the womb (endometrial cancer).
    • Women with untreated overgrowth of the lining of the womb (endometrial hyperplasia).
    • Women with vaginal bleeding where the cause is not known.
    • Women with blood disorders that increase the risk of blood clots in the veins, eg antiphospholipid syndrome, factor V Leiden, protein C deficiency, protein S deficiency or antithrombin deficiency.
    • Women with a blood clot in a vein of the leg (deep vein thrombosis) or in the lungs (pulmonary embolism).
    • Women with inflammation of a vein caused by a blood clot (thrombophlebitis).
    • Women who have recently had a stroke caused by a blood clot.
    • Women who have recently had a heart attack.
    • Women with angina pectoris.
    • Women with active liver disease, eg hepatitis, liver cancer, or a history of liver disease when liver function has not returned to normal.
    • Women who are pregnant or breastfeeding.
    • Women with rare hereditary problems of galactose intolerance, fructose intolerance, the Lapp lactase deficiency, glucose-galactose malabsorption or sucrase-isomaltase insufficiency (Premarin tablets contain lactose and sucrose).

    This medicine should not be used if you are allergic to one or any of its ingredients. Please inform your doctor or pharmacist if you have previously experienced such an allergy. If you feel you have experienced an allergic reaction, stop using this medicine and inform your doctor or pharmacist immediately.

    Pregnancy and breastfeeding

    Certain medicines should not be used during pregnancy or breastfeeding. However, other medicines may be safely used in pregnancy or breastfeeding providing the benefits to the mother outweigh the risks to the unborn baby. Always inform your doctor if you are pregnant or planning a pregnancy, before using any medicine.

    • This medicine should not be used by women who are pregnant or breastfeeding. You should stop taking this medicine and consult your doctor immediately if you think you could be pregnant during treatment.
    • A woman is considered fertile for two years after her last menstrual period if she is under 50, or for one year if over 50. HRT does not provide contraception for women who fall within this group. If you could get pregnant while taking this HRT, you should use a non-hormonal method of contraception (eg condoms or contraceptive foam). Seek further medical advice from your doctor.

    Possible side effects of Premarin

    Medicines and their possible side effects can affect individual people in different ways. The following are some of the side effects that are known to be associated with this medicine. See also the important information section above. Just because a side effect is stated here, it does not mean that all women using this medicine will experience that or any side effect.

    • Gut disturbances, such as nausea and vomiting, abdominal pain, bloating, flatulence, indigestion.
    • Menstrual bleeding or spotting. See important information above.
    • Vaginal thrush.
    • Increase in the size of uterine fibroids.
    • Breast pain, tenderness or enlargement.
    • Fluid retention, causing swelling (oedema).
    • Headache or migraine.
    • Premenstrual-like symptoms.
    • Depression, anxiety or mood changes.
    • Changes in sex drive.
    • Fatigue.
    • Dizziness.
    • Weight changes.
    • Leg cramps.
    • Rise in blood pressure.
    • Steepening of corneal curvature, which may make contact lenses uncomfortable.
    • Skin reactions such as rash and itching.
    • Irregular brown patches on the skin, usually of the face (chloasma).
    • Disturbance in liver function and jaundice.
    • Gallbladder disease.
    • Inflammation of the pancreas (pancreatitis).
    • Blood clots in the blood vessels.

    The side effects listed above may not include all of the side effects reported by the medicine's manufacturer. For more information about any other possible risks associated with this medicine, please read the information provided with the medicine or consult your doctor or pharmacist.

    How can Premarin affect other medicines?

    It is important to tell your doctor or pharmacist what medicines you are already taking, including those bought without a prescription and herbal medicines, before you start treatment with this medicine. Similarly, check with your doctor or pharmacist before taking any new medicines while taking this one, to make sure that the combination is safe.

    The following medicines may potentially reduce the blood level and effect of this medicine, which could cause irregular menstrual bleeding or your symptoms to come back:

    • aprepitant
    • bosentan
    • barbiturates
    • carbamazepine
    • cobicistat
    • crizotinib
    • dabrafenib
    • efavirenz
    • eslicarbazepine
    • fosaprepitant
    • fosphenytoin
    • modafinil
    • nevirapine
    • oxcarbazepine
    • phenobarbital
    • phenytoin
    • primidone
    • rifabutin
    • rifampicin
    • ritonavir
    • rufinamide
    • telaprevir
    • the herbal remedy St John's wort (Hypericum perforatum)
    • topiramate
    • vemurafenib.

    Some women with diabetes may need small adjustments in their dose of insulin or antidiabetic tablets while taking this medicine. You should monitor your blood sugar and seek advice from your doctor or pharmacist if your blood sugar control seems to be altered after starting this medicine.

    This medicine may oppose the effect of medicines used to lower high blood pressure. Your blood pressure will usually be checked periodically while you are taking HRT, but this is particularly important if you are also taking medicines for high blood pressure.

    This medicine may also oppose the fluid-losing effect of diuretic medicines.

    This medicine may decrease the amount of the antiepileptic medicine lamotrigine in the blood. As this could increase the risk of seizures coming back or getting worse, the medicine may not be recommended for women who take lamotrigine on its own for epilepsy.

    This medicine may increase the blood levels of the following medicines and this could possibly increase the risk of their side effects:

    • aminophylline
    • ropinirole
    • selegiline
    • theophylline
    • tizanidine.

    References:

    http://www.netdoctor.co.uk/medicines/a7384/premarin-conjugated-oestrogens/

    https://www.drugs.com/premarin.html

    https://www.premarin.com

    https://en.wikipedia.org/wiki/Premarin

    http://www.rxlist.com/premarin-side-effects-drug-center.htm

    https://www.medicines.org.uk/emc/medicine/27266