Tamoxifen

Hormones are chemicals that our bodies make. Hormones act as messengers and help control how cells and organs work. Hormonal therapies are drugs that change the way hormones are made or how they work in the body.

Many breast cancers rely on the hormone oestrogen to grow. This type of breast cancer is called oestrogen receptor-positive (ER-positive) breast cancer. Tamoxifen blocks oestrogen from reaching the cancer cells.

Tamoxifen comes as tablets or syrup you can take at home. You may have tamoxifen on its own, or with other drugs. Your nurse or doctor will talk to you about your treatment plan. 

Always take the tablets or syrup exactly as explained. This is important to make sure they work as well as possible for you. For the treatment or prevention of cancer, you usually take tamoxifen daily. Try to take it at the same time every day. 

If you forget to take your tamoxifen, you should take the missed dose as soon as possible within the same day. If a full day has passed, let your doctor or nurse know. Do not take a double dose unless your doctor tells you to.

Other things to remember about your tablets or syrup:

• Keep them in the original package and at room temperature, away from heat and direct sunlight.
• Keep them safe and out of sight and reach of children.
• If you are sick just after taking the tablets or syrup, contact your healthcare team. Do not take another dose.
• Get a new prescription before you run out of tablets or syrup, and make sure you have plenty for holidays.
• If your treatment is stopped, return any unused tablets or syrup to the pharmacist. 

Your nurse or pharmacist may also give you other medicines to take home. Take all your medicines exactly as they have been explained to you. Do not stop taking any of your medicines unless your doctor tells you to. 

Hot flushes are a common side effect of this treatment. During a flush, your neck and face may feel warm. If you have white skin, your skin may look red. If you have black or brown skin, your skin colour may deepen. Flushes can last up to 5 minutes. You might also have sweats or feel anxious or irritable during a flush. 

Here are some things you can do to reduce the effects of hot flushes:

• Wear natural fabrics, such as cotton.
• Wear layers so you can remove clothes as needed. 
• Use cotton sheets and layers of bedding you can remove. 
• Try cooling pads or pillows to keep you cool.
• Keep rooms cool or use a fan.
• Have cold drinks and avoid caffeine and alcohol. 

You might have fewer hot flushes as your body adjusts to this treatment. You could try therapies to help you cope with hot flushes, such as:

• talking therapies like cognitive behaviour therapy (CBT)
• controlled breathing exercises
• yoga
• acupuncture. 

If they do not improve, talk to your doctor. Certain drugs can help to improve hot flushes. 

Flushes usually stop a few months after treatment ends. But some people continue to have them.

This treatment can cause vaginal dryness and itching. 

If you have this side effect, non-hormonal creams, gels or lubricants may help. You can buy these from a chemist, or your doctor can prescribe them. We have more information about cancer and sex. 

This treatment can cause vaginal bleeding or change the usual pattern of periods.

You may have bleeding when you start this treatment, or if you change to it from another treatment. If bleeding continues for more than a few days, tell your doctor or nurse. 

If you have periods, you may find they become irregular, lighter, or sometimes stop altogether during this treatment. This does not always mean you are unable to get pregnant. Even if your periods stop or are irregular when taking this treatment, you still need to use contraception to prevent a pregnancy. Your doctor or nurse can tell you more about this.

This treatment can make you feel sick. Any sickness usually improves after a few weeks. Try taking tamoxifen with food or at night.

Let your doctor or nurse know if you continue to feel sick. They can give you advice or drugs to help.

Feeling tired is a common side effect. Try to pace yourself and plan your day so you have time to rest between activities.

Being physically active can help to manage tiredness and give you more energy. It also:

• helps you sleep better
• reduces stress
• improves your bone health.

If you feel sleepy, do not drive or operate machinery.

You may feel low or depressed, or have mood swings, during this treatment. Talking to family and friends about how you feel might help. If mood changes last for more than a few weeks, tell your doctor, nurse or pharmacist. They can talk to you about different ways to manage low mood or depression.

This treatment may affect your skin. It may cause a rash, which might be itchy. Your doctor or nurse can tell you what to expect. If your skin feels dry, try using an unperfumed moisturising cream every day.

Always tell your doctor or nurse about any changes to your skin. They can give you advice and may prescribe creams or medicines to help. Skin changes usually improve when treatment finishes.

Rarely, this treatment may cause a more serious skin condition. You may have a skin rash which then blisters and your skin can peel. You may also feel unwell with flu-like symptoms such as a high temperature and joint pain. If you have any of these symptoms, you should stop taking tamoxifen and contact the hospital straight away.

While you are having this treatment, your hair may become thinner, drier and more brittle. This is usually mild. If you are worried about this, ask your nurse for advice on hair care.

You may find your ankles or fingers become swollen when taking this drug. 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 your nurse or doctor for advice.

Walking may stretch the muscles and help with this. Let your doctor or nurse know if leg cramps or muscle pains are a problem.

This treatment may cause headaches. If you have headaches, tell your doctor, nurse or pharmacist. They can give you advice about painkillers that may help. Tell them if the headache does not get better, or gets worse.

This treatment can cause constipation or diarrhoea. If this is a problem, tell your doctor or nurse.

This treatment may cause cataracts (clouding of the lens of the eye) or other eye problems. If you get blurry vision or notice any change in your vision, always tell your doctor or nurse. If your vision is affected, it is important not to drive or operate machinery.

This treatment can affect the nervous system. You may have pins and needles, or feel tingling in your arms and legs. You may also feel dizzy or unsteady, or have taste changes. Tell your doctor or nurse if you notice any of these symptoms.

It is important not to drive or operate machinery if you feel dizzy.

Tamoxifen increases the risk of a blood clot or stroke. Your doctor will give you advice about reducing this risk. They may give you drugs to reduce your risk while you are taking tamoxifen. 
Symptoms of a blood clot include:

• throbbing pain, redness or swelling in a leg or arm
• suddenly feeling breathless or coughing
• sharp chest pain, which may be worse when you cough or take a deep breath. 

Symptoms of a stroke include:

• the face, mouth or eye may have drooped on one side
• weakness or numbness in one arm
• problems with speech, talking or understanding.

If you have any of these symptoms, contact the hospital straight away on the 24-hour contact number you have been given. If you cannot get through to your doctor, call the NHS urgent advice number on 111.

This treatment can cause changes to the lining of the womb that may cause vaginal bleeding. Rarely, tamoxifen can cause womb cancer.

The benefits of taking tamoxifen usually outweigh the risk of womb cancer. Always tell your doctor if you have irregular or unexpected bleeding or discharge from the vagina. They will arrange tests if needed to check for changes to the lining of the womb.

You should also tell them if you have any pain or pressure in the lower tummy (pelvis). This can be an early sign of womb cancer, although it is usually caused by other conditions. If womb cancer is found early, treatment can be very successful.

This treatment may affect how your liver works. This is usually mild. You will have blood tests to check how well your liver is working.

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