Flutamide (Drogenil ®)
Flutamide (Drogenil ®) is a hormonal therapy used to treat prostate cancer. This page describes what flutamide is, how it's given and some of its possible side effects. It should ideally be read with our general information about prostate cancer.
Hormones are substances that are produced naturally in the body. They act as chemical messengers and help control the activity of cells and organs. Hormonal therapies such as flutamide work by interfering with the production or action of particular hormones in the body.
You will see your doctor regularly while you have this treatment so 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.
Most prostate cancers need supplies of the male sex hormone testosterone to grow. Testosterone is produced by the testes and the adrenal glands. Prostate cancer cells have proteins called receptors, which sex hormones attach to. When testosterone attaches to these receptors, it causes cancer cells to grow.
Flutamide has a structure similar to testosterone. It works by preventing testosterone from attaching (binding) to the receptors. Without testosterone, the cancer cells either grow more slowly or stop growing altogether.
How flutamide is taken
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Flutamide is a tablet that is taken three times a day. Doses should be evenly spaced throughout the day.
Flutamide is given to treat prostate cancer that has spread to other parts of the body (advanced prostate cancer). It may be given on its own or in combination with injections of goserelin, triptorelin, buserelin or leuprorelin. These are all hormonal therapy drugs known as LHRH (luteinising hormone releasing hormone) analogues. LHRH drugs block the production of luteinising hormone produced by the pituitary gland, which normally stimulates the production of testosterone.
Flutamide can also be used to help prevent tumour flare. This is a temporary increase in symptoms, such as bone pain, that can occur when a man first starts treatment with an LHRH analogue.
Your doctor will discuss the length of treatment they feel is appropriate for your situation. Flutamide is often given for several months or even years. Treatment with flutamide may continue for as long as it is effective in controlling your cancer.
Each person's reaction to any medication is different. Many people have very few side effects with flutamide, while others may experience more. The side effects described here won't affect everyone and may be different if you are having more than one drug.
We have outlined the most common side effects here and have included those that are rarer underneath. If you notice any effects that aren't listed here, discuss them with your doctor or nurse.
You may have some of the following side effects, to varying degrees.
Breast tenderness or fullness
Some men may notice slight breast swelling and tenderness known as gynaecomastia. Your doctor can advise you about how this can be treated or prevented.
This occurs quite commonly and may be accompanied by abdominal cramps. Diarrhoea can usually be easily controlled, but occasionally it may be severe. It's important to tell your doctor if this occurs, as it may be necessary to reduce or discontinue treatment with flutamide and consider other types of hormonal therapy.
Feeling sick (nausea) or being sick (vomiting)
If these effects occur they can usually be effectively treated. Let your doctor know if you feel sick or are being sick.
Loss of sex drive (libido) and erection difficulties (impotence) can occur in some men. These effects will usually return to normal after hormonal therapy is stopped. Let your doctor know if you have either of these side effects, as they may be able to prescribe medication to help. You might find it helpful to see our section on sexuality and cancer.
You may feel lethargic and have trouble sleeping. It's important to get plenty of rest.
Less common side effects
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Effect on liver function
Your doctor will take blood samples to measure how well your liver is working. This is because flutamide can sometimes cause the amount of particular chemicals produced by the liver to change. If this happens, the drug will be stopped and liver function usually returns to normal. Yellowing of the skin or eyes could be a sign that your liver isn’t working properly. Tell your doctor if you notice this.
A rare side effect of flutamide is blurred vision. This may develop a few months after treatment has started.
Always let your doctor or nurse know about any side effects you have. There are usually ways in which they can be controlled or improved.
Things to remember about flutamide tablets
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Flutamide may interact with other medicines. Tell your doctor about any medications you're taking. This includes non-prescribed drugs such as complementary therapies, vitamins and herbal drugs.
Keep the tablets in a safe place, out of the reach of children.
If your doctor decides to stop the treatment, return any remaining tablets to the pharmacist. Don't flush them down the toilet or throw them away.
Don't worry if you forget to take your tablet. Do not take a double dose. The levels of the drug in your blood will not change very much, but try not to miss more than one or two tablets in a row.
Remember to get a new prescription a few weeks before you run out of tablets and make sure that you have plenty for holidays.
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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.
It’s a good idea to know who you should contact if you have any problems or troublesome side effects when you’re at home. You can ask your doctor or nurse about this if you’re not sure.
This section has been compiled using information from a number of reliable sources, including:
Sweetman, et al. Martindale: The Complete Drug Reference. 37th edition. 2011. Pharmaceutical Press.
British National Formulary. 63rd edition. 2012. British Medical Association and Royal Pharmaceutical Society of Great Britain.
Thank you to Kavita Kantilal, E-Prescribing Pharmacist, and all of the people affected by cancer who reviewed this edition. Reviewing information is just one of the ways you could help when you join our Cancer Voices network.