Estradiol (Estring)

How does it work?

Estring vaginal ring contains the active ingredient estradiol hemihydrate (previously spelt oestradiol hemihydrate in the UK), which is 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 and often affect the delicate lining of the vagina. Oestrogen deficiency can cause vaginal dryness, inflammation or itching, and this in turn can lead to sex being uncomfortable or painful, and to an increased susceptibility to vaginal or urinary infections.

Oestrogen can be given as a supplement to replace the falling levels in the body and help reduce the distressing symptoms of the menopause. This is known as hormone replacement therapy (HRT). Oestrogen (in this case in the form of estradiol hemihydrate) can also be inserted directly into the vagina, in order to directly supplement the vaginal tissues with oestrogen. This is known as topical HRT and is useful for relieving just the vaginal symptoms of the menopause.

Estring is a flexible silicon ring that is worn in the vagina continuously for three months. It releases oestrogen locally into the vaginal tissues and is used short-term to provide relief from the vaginal symptoms of the menopause, such as dryness, itching and irritation. The ring can be replaced as necessary every three months, but should be used for as short a time as possible and should not be used continuously for longer than two years. Use of the ring should be reviewed with your doctor at least once a year.

Estradiol from Estring is only absorbed from the vagina into the bloodstream to a very small extent. However, this means it may potentially be associated with the same risks as other forms of HRT and so carries the same warnings (see below). These warnings are most relevent to repeated or long-term use of the ring. You can read more about the risks and benefits of HRT in the factsheet about the menopause linked below.

What is it used for?

  • Vaginal symptoms of the menopause (atrophic vaginitis)

Warning!

  • Follow the instructions provided with your Estring vaginal ring carefully.
  • Using oestrogen-only HRT tablets or patches for a long time can increase the risk of cancer of the lining of the womb (the endometrium). It is possible there may be a similar risk when oestrogen rings or creams are used in the vagina for repeated treatments, or over a long period of time. If you experience any vaginal bleeding or spotting, abnormal vaginal discharge or vaginal discomfort while you are using Estring, you should consult your doctor so that this can be investigated.
  • Women using any form of HRT should have regular medical and gynaecological check-ups. Your need for continued HRT should be reviewed with your doctor at least once a year.
  • It is important to be aware that women using HRT have an increased risk of being diagnosed with breast cancer compared with women who don't use HRT. This risk needs to be weighed against the personal benefits to you of taking HRT. There is more detailed information about the risks and benefits associated with HRT in the factsheet about the menopause linked above. You should discuss these with your doctor before starting HRT. Women on HRT should have regular breast examinations and mammograms and should examine their own breasts regularly. Report any changes in your breasts to your doctor or nurse.
  • It is important to be aware that women using HRT have a slightly increased risk of stroke and of blood clots forming in the veins (eg deep vein thrombosis/pulmonary embolism) compared with women who don't use HRT. The risk is higher if you have existing risk factors (eg personal or family history, smoking, obesity, certain blood disorders - see cautions below) and needs to be weighed against the personal benefits to you of taking HRT. There is more detailed information about the risks and benefits associated with HRT in the factsheet about the menopause linked above. Discuss these with your doctor before starting treatment.
  • The risk of blood clots forming in the veins (thromboembolism) while taking HRT may be temporarily increased if you experience major trauma, have surgery, or are immobile for prolonged periods of time (this includes travelling for over five hours). For this reason, your doctor may recommend that you stop using HRT for a period of time (usually four to six weeks) prior to any planned surgery, particularly abdominal surgery or orthopaedic surgery on the lower limbs, or if you are to be immobile for long periods. The risk of blood clots during long journeys may be reduced by appropriate exercise during the journey and possibly by wearing elastic hosiery. Discuss this with your doctor.
  • Stop using this medicine and inform your doctor immediately if you experience any of the following symptoms while using this medicine: stabbing pains or swelling in one leg; pain on breathing or coughing; coughing up blood; breathlessness; sudden chest pain; sudden numbness affecting one side or part of the body; fainting; worsening of epilepsy; migraine or severe headaches; visual disturbances; severe abdominal complaints; increased blood pressure; itching of the whole body; yellowing of the skin or eyes (jaundice); or severe depression.

Use with caution in

  • Close family history of breast cancer (eg mother, sister or grandmother has had the disease)
  • History of benign breast lumps (fibrocystic breast disease)
  • History of fibroids in the womb
  • History of endometriosis
  • History of overgrowth of the lining of the womb (endometrial hyperplasia)
  • Personal or family history of blood clots in the veins (venous thromboembolism, eg deep vein thrombosis or pulmonary embolism)
  • Blood disorders that increase the risk of blood clots in the veins, eg antiphospholipid syndrome, factor V Leiden
  • Women taking medicines to prevent blood clots (anticoagulants), eg warfarin
  • Long-term inflammation of skin and some internal organs (systemic lupus erythematosus)
  • Personal or family history of recurrent miscarriage
  • Severe obesity
  • Varicose veins
  • Smokers
  • History of high blood pressure (hypertension)
  • Raised levels of fats called triglycerides in the blood (hypertriglyceridaemia)
  • History of liver disease, eg liver cancer
  • Decreased kidney function
  • Heart failure
  • History of diabetes
  • History of gallstones
  • History of migraines or severe headaches
  • History of epilepsy
  • History of asthma
  • History of an ear disorder that may cause hearing loss (otosclerosis)
  • 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).

Not to be used in

  • Known, suspected, or past history of breast cancer
  • Known or suspected cancer in which growth of the cancer is stimulated by oestrogen, eg cancer of the lining of the womb (endometrial cancer)
  • Untreated overgrowth of the lining of the womb (endometrial hyperplasia)
  • Vaginal bleeding of unknown cause
  • Women with a blood clot in a vein of the leg (deep vein thrombosis) or in the lungs (pulmonary embolism), or a past history of these conditions where the cause is unknown
  • Women who have recently had a stroke caused by a blood clot
  • Women who have recently had a heart attack
  • Angina pectoris
  • Active liver disease
  • History of liver disease when liver function has not returned to normal
  • Hereditary blood disorders known as porphyrias
  • Pregnancy
  • Breastfeeding.

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 using this medicine and consult your doctor immediately if you get pregnant during treatment.

Side effects

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. Because a side effect is stated here, it does not mean that all people using this medicine will experience that or any side effect.

  • Vaginal irritation
  • Abdominal pain or discomfort
  • Vaginal infection
  • Vaginal itching
  • Feeling of pressure in the vagina, or on the bladder or rectum
  • Itching
  • Urinary tract infection
  • Increased sweating.

In addition, the following side effects have been associated with oestrogens for HRT, taken as tablets, skin patches or gels, or implants, but due to the low absortion of oestrogen from Estring these are unlikely to occur with short-term use of Estring:

  • Breakthrough bleeding and spotting
  • Breast pain, tenderness or enlargement
  • Headache/migraine
  • Gut disturbances, such as nausea, abdominal pain, bloating, flatulence, indigestion
  • Leg cramps
  • Fatigue
  • Weight changes
  • Vaginal thrush
  • Overgrowth of the womb lining (endometrial hyperplasia)
  • Depression
  • Anxiety
  • Dizziness
  • Changes in sex drive
  • Rise in blood pressure
  • Gall bladder disease
  • Swelling of the ankles due to to fluid retention (peripheral oedema)
  • Skin reactions such as rash and itch
  • Steepening of corneal curvature which may make contact lenses uncomfortable.
  • Premenstrual-like symptoms
  • Disturbance in liver function
  • Irregular brown patches on the skin, usually of the face (chloasma)
  • Blood clots in the blood vessels (eg, DVT, pulmonary embolism, heart attack, stroke - see warnings above)

The side effects listed above may not include all of the side effects reported by the drug'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 this medicine affect other medicines?

As the estradiol from Estring is absorbed into the bloodstream only in very low amounts, it is not expected to significantly affect any other medicines that are being taken by mouth or injection.

However, you should always tell your doctor what medicines you are taking (including herbal medicines and those bought without a prescription) before you start treatment with this medicine. Similarly, always check with your doctor or pharmacist before taking any new medicines while using this one, to ensure that the combination is safe.

If you need to use any other vaginal medicines, for example pessaries or vaginal creams for thrush or other vaginal infections, your doctor may want you to remove your Estring during the treatment. Always check with your doctor.

Other medicines containing the same active ingredient

Aerodiol nasal spray Bedol Climaval
Elleste solo Elleste solo MX Estraderm MX
Estraderm TTSEstradiol implants Estradot
Evorel Fematrix FemSeven
FemTabOestrogel Progynova
Progynova TS SandrenaVagifem
Zumenon