What is diethylstilbestrol (Stilboestrol®)?

Diethylstilbestrol (Stilboestrol®) is a hormonal therapy drug used to treat prostate cancer. It is best to read this information with our general information about hormonal therapies and our information on advanced prostate cancer.

Your doctor will talk to you about this treatment and its possible side effects before you agree (consent) to have treatment. 

How diethylstilbestrol works

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.

Most prostate cancers need the hormone testosterone to grow. Almost all testosterone in men is made by the testicles. 

Diethylstilbestrol reduces the amount of testosterone made by your body. This reduces testosterone levels and may help to control the cancer. 

Taking diethylstilbestrol tablets

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

Always take the tablets exactly as explained. This is important to make sure they work as well as possible for you. Make sure you:

  • swallow them whole with a glass of water
  • take them at the same time every day.

If you forget to take the tablets, 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:

  • 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, contact your healthcare team. Do not take another dose.
  • Get a new prescription before you run out of tablets, and make sure you have plenty for holidays.
  • If your treatment is stopped, return any unused tablets 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.

About side effects

We explain the most common side effects of this treatment here. We also include some less common side effects.

You may get some of the side effects we mention, but you are unlikely to get all of them. If you are also having treatment with other cancer drugs, you may have some side effects that we have not listed here. Always tell your doctor, nurse or pharmacist about any side effects you have.

Your doctor can give you drugs to help control some side effects. It is important to take them exactly as your nurse or pharmacist explains. This means they will be more likely to work for you. Your nurse will give you advice about managing your side effects. After your treatment is over, most side effects start to improve.

Serious and life-threatening side effects

Some cancer treatments can cause severe side effects. Rarely, these may be life-threatening. Your cancer doctor or nurse can explain the risk of these side effects to you.

Contact the hospital

Your nurse will give you telephone numbers for the hospital. If you feel unwell or need advice, you can call them at any time of the day or night. Save these numbers in your phone or keep them somewhere safe.

More information

We cannot list every side effect for this treatment. There are some rare side effects that are not listed. You can visit the Medicines and Healthcare products Regulatory Agency for more detailed information.

Common side effects

Allergic reaction

Some people have an allergic reaction while having this treatment. Signs of a reaction can include:

  • feeling hot or flushed
  • a skin rash
  • itching
  • shivering
  • feeling dizzy
  • a headache
  • feeling breathless.

If you feel unwell or have any of these signs, tell a doctor or nurse straight away. Do not take any more of this treatment until you have spoken to them.

Breast swelling or tenderness

This treatment may cause swelling and tenderness of your breast tissue. This is called gynaecomastia. Your doctor can give you advice on preventing and treating this.

Sexual effects

Most men lose their sex drive and have erection problems during hormonal therapy. Things often return to normal after you stop taking the drug. But some men continue to have problems after treatment is over. Your doctor can prescribe treatments to help with erection problems. But these treatments will not increase your sex drive.

Build-up of fluid (oedema)

Sometimes fluid can build up in your legs and ankles. This can cause swelling. This is known as oedema. Tell your doctor or nurse if you have any swelling. If your ankles and legs swell, it can help to put your legs up on a foot stool or cushion. The swelling usually gets better after your treatment ends.

Feeling sick

This is usually mild. Your doctor can prescribe anti-sickness drugs if you need them.

Tiredness

Feeling tired is a common side effect. Try to pace yourself and plan your day so you have time to rest. Gentle exercise, like short walks, can give you more energy. If you feel sleepy, do not drive or operate machinery.

Headaches

This treatment may cause headaches. If this happens, tell your doctor or nurse. They can give you painkillers.

If you had migraines (a severe type of headache) before starting diethylstilbestrol, these may get worse. Let your doctor know if are having more headaches than usual.

Skin changes

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

Diethylstilbestrol can make some areas of skin darken. Protecting your skin from the sun may help reduce this. Use a high factor suncream (SPF 30 or above) on all areas of your skin before going out in the sun.

Always tell your doctor or nurse about any skin changes. They can give you advice and may prescribe creams or medicines to help.

Weight gain and loss of muscle strength

This treatment may make you put on weight and you may lose some muscle strength. Eating healthily and being active can help.

Mood changes

You may have some mood changes during this treatment. You may feel low or depressed. Let your doctor or nurse know if you notice any changes.

High blood pressure (hypertension)

Diethylstilbestrol may cause an increase in blood pressure. You may have regular blood pressure checks when taking this drug.

Tell your doctor if you have high blood pressure before you start taking this drug.

Raised blood sugar levels

This treatment can raise your blood sugar levels. If you have a raised blood sugar level, you may:

  • feel thirsty
  • need to pass urine (pee) more often
  • feel tired.

Tell your doctor or nurse if you have these symptoms.

If you have diabetes, your blood sugar levels may be higher than usual. Your doctor will talk to you about how to manage this. You may need to change your insulin or tablet dose.

Effects on the gall bladder or liver

Rarely, this drug can cause gallstones and jaundice. Tell your doctor straight away if you notice your skin or the whites of your eyes becoming yellow

Effects on the eyes

Diethylstilbestrol can cause eye discomfort in contact lens wearers. Tell your doctor if you experience this.

Muscle or joint pain

You may get pain in your muscles or joints. If this happens, tell your doctor so they can give you painkillers. Being physically active may help with the pain and keep your joints flexible. Keeping to a healthy weight may help too. Tell your doctor or nurse if the pain does not get better.

Blood clot risk

Cancer and some cancer treatments can increase the risk of a blood clot. Symptoms of a blood clot include:

  • pain, redness or swelling in a leg or arm
  • breathlessness
  • chest pain.

If you have any of these symptoms, contact a doctor straight away.

A blood clot is serious, but can be treated with drugs that thin the blood. Your doctor or nurse can give you more information. 

Your doctor may prescribe a low dose of aspirin while you are taking diethylstilbestrol. This helps to prevent blood clots.

Other information

Lactose

Diethylstilbestrol contains a small amount of lactose. If you have a lactose intolerance, talk to your doctor before you start taking this.

Other medicines

Some medicines can affect how this treatment works or be harmful when you are having it. Always tell your cancer doctor about any drugs you are taking or planning to take, such as:

  • medicines you have been prescribed
  • medicines you buy in a shop or chemist
  • vitamins, herbal drugs and complementary therapies.

Tell other doctors, pharmacists or dentists who prescribe or give you medicines that you are having this cancer treatment.

You can visit the Medicines and Healthcare products Regulatory Agency (MHRA) for more detailed information about your treatment.

Contraception

Your doctor will advise you not to make someone pregnant while having this treatment. The drug may harm the developing baby. It is important to use effective contraception during your treatment.

Medical and dental treatment

If you need medical treatment for any reason other than cancer, always tell the doctors and nurses that you are having cancer treatment. Give them the contact details for your cancer doctor so they can ask for advice.

If you think you need dental treatment, talk to your cancer doctor or nurse. Always tell your dentist you are having cancer treatment.