Toremifene (Fareston ®)
Toremifene is a hormonal therapy drug used to treat breast cancer. This information is best read with our information about secondary breast cancer.
You will see your doctor regularly while you have this treatment so that they can monitor its effects. This information should help you discuss any queries about your treatment and its side effects with your doctor or specialist nurse.
Hormones are substances produced naturally in the body. They act as chemical messengers and help control the activity of cells and organs. Hormonal therapies interfere with the way hormones are made or how they work in the body.
Many breast cancers rely on the hormone oestrogen to grow. This is called oestrogen receptor-positive (ER positive) breast cancer. Toremifene blocks oestrogen from reaching the cancer cells. This means the cancer either grows more slowly or stops growing altogether.
When toremifene is used
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Toremifene may be used to treat women with ER positive breast cancer, and who have been through the menopause. It is usually used to treat breast cancer that has spread to other areas of the body (secondary breast cancer).
Toremifene may be taken for as long as it is effective in controlling the cancer. Your doctors will discuss the length of treatment they feel is appropriate for your situation.
Taking your toremifene tablets
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You take toremifene as a tablet, usually once a day. You take it at the same time each day, morning or evening. Always take your tablets exactly as your nurse or pharmacist explained. This is important to make sure they work as well as possible for you.
There are some important things to remember when taking your tablets:
Do not eat grapefruit or drink grapefruit juice when you take toremifene.
Don’t take a double dose if you forget to take your tablet.
Keep tablets in the original package, and at room temperature away from heat and direct sunlight.
Keep them safe and out of the reach of children.
Get a new prescription before you run out of tablets, and make sure you have plenty for holidays.
Return any remaining tablets to the pharmacist if your treatment is stopped.
Possible side effects of toremifene
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We explain the most common side effects of toremifene here. But we don’t include all the rare ones that are unlikely to affect you. You may get some of the side effects we mention, but you are very unlikely to get all of them. If you are having other drugs as well, you may have some side effects that we don’t list here.
Always tell your doctor or nurse about the side effects you have. They can prescribe drugs to help control them and give you advice about managing them. Don’t stop taking toremifene without talking to your doctor first.
Hot flushes and sweats
These are common side effects. They may gradually lessen over the first few months, but some women continue to have them for as long as they take toremifene.
Cutting down on nicotine, alcohol and hot drinks containing caffeine, such as tea and coffee, can help. Dress in layers, so you can remove clothes as needed. Natural fabrics, such as cotton, may feel more comfortable.
If hot flushes are troublesome, tell your doctor. Low doses of certain antidepressant drugs can help to reduce flushes.
You can read more about treatments for menopausal symptoms like hot flushes in our section on breast cancer and menopausal symptoms.
Some women have a vaginal discharge or bleeding from the vagina when on this treatment. It’s always important to tell your doctor or nurse if you notice any unusual bleeding from your vagina.
You may feel sick at times when you start taking toremifene. This often lessens or goes away after a few weeks. Taking your tablet with food or milk, or at night may help.
You may feel more tired than usual. Try to balance rest periods with some physical activity such as short walks. Doing this can help you to feel less tired.
Fluid build-up (oedema)
Some women may have swollen ankles or fingers when taking toremifene. This is caused by a build up of fluid, which is called oedema. It is usually mild. If you notice any swelling or puffiness, ask you nurse or doctor for advice.
Effects on the skin
Toremifene can cause a rash or itchy skin. These effects are usually mild. Tell your doctor if you develop a rash or itching. They may prescribe drugs or creams to help.
Dizziness or changes in vision
Some women may feel dizzy. Rarely, they may have blurred vision or changes in their eyesight. These side effects may be worse if you take toremifene with alcohol. Always tell your doctor or nurse if you have any of these side effects. Don’t drive or operate machinery if you have them.
Changes in mood
You may have mood changes or feel low or depressed when taking toremifene. Talk to your nurse or doctor if this happens. They can suggest ways to help with this.
Less common side effects of toremifene
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Blood clots (thrombosis)
This is rare. Signs of a blood clot include pain, warmth, swelling or tenderness in an arm or leg, or chest pain. Tell your doctor immediately if you have any of these signs. Toremifene isn't usually given to people who have had a blood clot in the past.
Increased risk of womb cancer
Women who have been through menopause, and take toremifene over a long period of time have a slightly increased risk of cancer of the womb. But this risk outweighs the benefits of taking toremifene. Your doctor may arrange for you to have yearly tests to check your womb while you are taking the drug. When womb cancer is found, early treatment is very successful.
Vaginal bleeding after the menopause can be an early sign of womb cancer, although it is more commonly caused by conditions other than cancer. Always tell your doctor if you have vaginal bleeding so they can check for the cause.
Changes in heart rhythm
A small number of people develop changes in their heartbeat when on this drug. Tell your doctors if you have ever had heart rhythm changes or any other problems with your heart in the past. You should also tell them if you’re taking any medicines for your heart. If you notice a change in your heartbeat it’s important to tell your doctor. They may do a test to check your heart rhythm (ECG).
Toremifene can interact with other drugs. This includes medicines you can buy in a shop or chemist. Tell your doctor about any medicines you are taking, including ones you can buy for yourself, complementary therapies and herbal drugs.
Medical or dental treatment
If you need to go into hospital for any reason other than cancer, always tell the doctors and nurses that you are taking toremifene. Explain you are taking hormonal therapy that no one should stop or restart without checking with your cancer doctor first. Tell them the name of your cancer doctor so they can ask for advice.
Always tell your dentist you are taking toremifene.
The information in this section has been produced in accordance with the following source and guideline:
If you’d like further information on the sources we use, please feel free to contact us.
Thanks to Penny Daynes, Oncology/Haematology Pharmacist, who reviewed this edition.
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