Diethylstilbestrol (Stilboestrol ®)
Diethylstilbestrolis is a hormonal therapy drug used to treat prostate cancer. It’s also called Stilboestrol. It’s best to read this information with our general information about prostate cancer.
How diethylstilbestrol works
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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.
Most prostate cancers need the hormone testosterone to grow. Almost all testosterone in men is made by the testicles. A very small amount is made by the adrenal glands, which sit above the kidneys. Diethylstilbestrol reduces the amount of testosterone made by your body. This reduces testosterone levels and may shrink the prostate cancer or stop it growing.
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Diethylstilbestrol is a tablet. You take it once a day at the same time each day. 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. Here are some important things to remember when taking your tablets:
If you forget to take your tablet, take one as soon as you remember, unless it’s nearly time for your next one – don’t take a double dose.
Keep tablets in the original package 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.
Your doctor will discuss with you the length of treatment they feel is appropriate. Treatment may continue for as long as it is effective in controlling your cancer.
Possible side effects of diethylstilbestrol
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We explain the most common side effects of diethylstilbestrol 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 cancer doctor or nurse about the side effects you have. They can prescribe drugs to help control some side effects and give you advice about managing side effects.
Breast swelling or tenderness
Some men may get breast swelling or tenderness (known as gynaecomastia). Your doctor can advise you about how this can be treated or prevented.
Most men lose their sex drive and have erection difficulties during hormonal therapy. These often return to normal after you stop taking the drug, but some men continue to have difficulties after treatment is over. Your doctor can prescribe treatments to help with erection difficulties but these don’t affect sex drive.
If you need support coping with sexual difficulties, your nurse or doctor can give you information and refer you for specialist support services.
Build-up of fluid
You may put on weight or your ankles and legs may swell because of fluid building up. Tell your doctor or nurse if this happens. If your ankles and legs swell it can help to put your legs up on a footstool with a pillow.
This is usually mild. Your doctor can prescribe anti-sickness drugs if needed.
You may feel tired and lack energy while taking diethylstilbestrol. Try to pace yourself if you feel tired. Aim for a balance between resting and being physically active. There is evidence that regular exercise can reduce tiredness in men on hormonal therapy. Ask your doctor or nurse what is safe for you to do.
This treatment can cause headaches in some men. 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.
Diethylstilbestrol can make some areas of skin darken. Protecting your face and neck from the sun may help reduce this. Use a high factor suncream (SPF 30 or above) on your face and neck before going out in the sun.
Weight gain and loss of muscle strength
You may gain weight, particularly around your waist, and you may lose some muscle strength. Eating a healthy diet and keeping physically active can help control your weight. Ask your doctor or nurse for advice.
You may experience mood swings. Tell your doctor if these are troublesome.
High blood pressure
Diethylstilbestrol may cause an increase in blood pressure. You may have regular blood pressure checks when taking this drug.
Blood clots (thrombosis)
Diethylstilbestrol can increase the risk of getting a blood clot. Tell your doctor immediately if you have chest pain or if you have redness, pain, warmth, swelling or tenderness in an arm or leg.
Some doctors may prescribe a low dose of aspirin while you are taking diethylstilbestrol to help prevent blood clots. It's important not to take drugs that contain aspirin unless they have been prescribed by your doctor.
Effects on gall bladder or liver
Rarely, this drug can cause gallstones. Tell your doctor immediately if you notice your skin or the whites of your eyes becoming yellow.
Contact lens wearers
Diethylstilbestrol can cause eye discomfort in contact lens wearers. Tell your doctor if you are affected.
If you have diabetes, your blood sugar levels may be higher than usual while on this drug. Your doctor will talk to you about how to manage this. You may need to change your insulin or tablet dose.
If you’re admitted to hospital for a reason not related to the cancer, it’s important to tell the doctors and nurses looking after you that you are having hormonal treatment. You should tell them the name of your cancer specialist so that they can ask for advice.
Diethylstilbestrol 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, vitamins and herbal drugs.
The information in this section has been produced in accordance with the following sources and guidelines:
MHRA. SPC Diethylstilbestrol (accessed June 2014).
electronic Medicines Compendium (eMC). www.medicines.org.uk (accessed June 2014).
NICE clinical guideline 175. Prostate cancer: diagnosis and treatment. 2014.
If you’d like further information on the sources we use, please feel free to contact us.
With thanks to Kavita Kantilal, E-Prescribing Pharmacist, who reviewed this information.
Thank you to all of the people affected by cancer who reviewed what you're reading and have helped our information to grow.
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