Toremefine (Fareston) 


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Your doctor has recommended a medication called toremifene. This page provides extra information about your medicine, summarises possible side effects and methods to alleviate them.

Toremifene is used to treat breast cancer and has a similar action to tamoxifenToremifene is taken by mouth in tablet form once a day at a dose of 60mg. Its trade name is Fareston

How do they work? Some tumours such as breast cancer are stimulated by the bodies own female hormone (Oestrogen). Stopping the bodies oestrogen reaching the tumour can cause the cancer cells to stop growing and in some cases shrivel up and die completely (self destruct - apoptosis).  Toremifene stops oestrogen stimulating a cancer cell by stopping the cancer cells ability to read the oestrogen in the blood stream. Breast cancer cells have receptors in the same way as a TV needs an aerial. If the aerial is damaged the TV can't show a clear picture. In the same way if the receptor on the cell is blocked it can't be influences by the bodies hormones, despite often normal levels in the blood stream. In this case the receptors is called oestrogen receptors and is blocked by  tamoxifen. This is way toremifene is sometimes referred to as a receptor antagonists. These receptors can be measures by performing a special test on the tissue removed from the tumour (Oestrogen receptor +ve). If a tumour is oestrogen receptor positive it is much more likely to respond . 

How are they taken? Toremifene is usually prescribed as a single daily dose. Many women like to take it at the same time each day – the actual time does not matter. Some women prefer to take it with food as it may cause nausea and leave a metallic taste in your mouth. Some women prefer to take it last thing at night because it reduces the hot flushes in the day . Try to find a convenient time and stick to it as its easier to remember to take the tablets in the long term.

If you forget to take your tablet don’t panic – levels of the drug in your blood will not change very much –   not to miss more than one or two tablets in a row. Remember to get a new prescription a couple of weeks before you run out of the tablets and make sure you have plenty for holidays etc.

What are the possible side effects of toremifene? Because people react to drugs in different ways, it is impossible to predict who is going to have side effects. Many women who take toremifene have no side effects at all while others will experience them. If side effects are severe, you may have to stop tasking the drug and a different hormonal drug may be prescribed.   Side effects are more common in pre-menopausal women who may develop menopausal side effects as a result of a reduced level of oestrogen. The commonest side effects, apart from nausea, are hot flushes and sweats, particularly at night.

  • Flushes and sweats

Sometimes the flushes will gradually lessen over the first few months but some women continue to have them for as long as they take toremifene. There are a number of ways to help reduce or control hot flushes and sweats. Some women find it helpful to avoid or cut down on tea, coffee, nicotine and alcohol. Evening primrose oil has been reported to be helpful in reducing sweats but it does not work for all women and it is very expensive. There are a lot of calories in Evening Primrose Oil so it may be fattening in some women. Some women have found complementary therapies have helped, and your GP may be able to give you details about obtaining these on the NHS. If you find your own therapist makes sure he or she is properly qualified and registered.

Sometimes another drug called clonidine (Dixarit) can be prescribed to reduce hot flushes and sweats.

A small dose of a progesterone may be a very helpful in controlling this unpleasant side effect but this does increase the risks of blood clots and can increase the risk of weight gain

If you are having very troublesome hot flushes do not hesitate to discuss some of these treatments with your doctor

  • Nausea and indigestion

Feelings of sickness (nausea) and indigestion are fairly common but can often be relieved by taking your tablet(s) with foods or milk or at night. Although mild nausea is quite common initially it usually wears off after a few weeks.

  • Weight gain

Weight gain can be a side effect of toremifene and this is sometimes due to water retention but at other times it may be a consequence of eating more either due to an increased appetite or mild nausea - "to settle the stomach" . 

  • Change in periods

Women who have not yet reached the menopause may notice their monthly periods change – they may become irregular, lighter or sometimes stop altogether. Some women also notice an increase in vaginal discharge and vulval itching.

Less common side effects include depression, tiredness and dizziness. Very rare side effect of toremifene includes:

  • Allergic reactions – this may include skin rashes
  • Temporary thinning of the hair
  • Headaches – some people affected by migraine have noticed a change in the pattern of their headaches
  • Flaking finger nails – after several years of treatment
  • Thrombosis (blood clots) – pain, warmth, swelling or tenderness in an arm or leg or any chest pain must be reported to your doctor immediately
  • Visual problems – blurred or reduced vision is again very rare but any visual changes should be reported to your doctor
  • Voice changes have been reported by some women – professional singers may want to seek help and advice.

Rarely, women who are prescribed toremifene for advanced cancer, where there has been spread to the bones, may experience something called ‘tumour flare’ when they start taking  Toremifene. This can cause a raised level of calcium in the blood (hypercalcaemia) with symptoms of nausea, vomiting and thirst. Often a short stay in hospital is necessary until the calcium levels have been reduced.

Toremifene can increase the effect of the drug warfarin, used I to thin the blood in people prone to blood clots. If you are taking warfarin let your doctor know straight away.

What are the long term side effects of toremifene?

As Toremifene is a relatively new drug the full long term effects of the drug are still being assessed through patient studies. In recent years there has been publicity about the long term effects of Toremifene and its possible link with other types of cancer.

Toremifene studies have shown that women who take high doses of Toremifene over a long period of time may have a slightly increased risk of developing cancer of the womb (endometrial cancer). Although no direct comparison has been performed as toremifene is a purer form of anti-oestrogen, in theory there is less risk than tamoxifen . This is very rare if the drug is taken for less than 5 years. However, this risk has to be weighted against the benefits of Toremifene. If detected early, treatment for endometrial cancer is usually very successful.

Early warning signs are abnormal vaginal bleeding – although this is often caused by a non-cancerous condition such as a polyp. If taken for longer than 5 years, in some cancer centres women are given regular gynaecological check-ups to detect signs of endometrial cancer. An ultrasound scan, using sound waves, may be done to check for signs of endometrial cancer. An ultrasound scan, using sound waves, may be done to check for signs of change in the womb lining. A small probe is inserted into the vagina and the doctor can look at the scan on a screen. Any changes can be seen straight away. The scan is safe and only takes a few minutes.

Other benefits of Toremifene There is some evidence suggesting that while you are taking tamoxifen it can lower the level of fat or lipids in your blood – and high levels of fat contribute to heart disease.

It is also thought that toremifene may help to prevent bone loss which can reduce the risk of osteoporosis (thinning of the bone) in some women.

Alternatives to Toremifene Tamoxifen is an alternative drug in all women and in post menopausal women it may be possible to take an aromatase inhibitor drug .

Further general information Your doctors and specialist nurses are in an ideal position to give you relevant information on your disease and treatment as they know your individual circumstances. Cancerbackup has a help line (0808 800 1234) and a prize winning video available in English, Italian, Urdu, Bengali, Gujarati & Hindi explaining Radiotherapy & Chemotherapy. has over 500 pages describing cancer, its management, practical tips and tool which patients, their carers and their doctors have found helpful during the cancer journey.

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