Fulvestrant is a type of hormone therapy drug used to treat breast cancer that has spread to other parts of the body in women who have gone through menopause.

HOW DOES FULVESTRANT WORK?

Hormones are substances produced naturally in the body. These act as chemical messengers and help control the activity of cells and organs. Hormone therapies interfere with the way hormones are made or formed in the body.

Many types of breast cancer depend on the hormone estrogen to grow. This type of breast cancer is called estrogen receptor-positive (ER-positive). These cancers have receptors (proteins) on the breast cancer cells that allow hormones like estrogen to attach themselves to the cell.

Fulvestrant blocks the receptors and stops estrogen from reaching the cancer cells. This slows or stops the growth of cancer cells. Fulvestrant also reduces the number of receptors on the breast cancer cells.

WHEN IS FULVESTRANT GIVEN?

Fulvestrant is usually given to women who have already received other hormone treatments but have ceased to control the cancer. Your doctor or nurse will explain how long you should take fulvestrant.

HOW IS FULVESTRANT GIVEN?

It is administered as two slow intramuscular injections, one in each buttock. It is given once a month, with an additional dose two weeks after the first dose only.

The injection may be somewhat uncomfortable, though it won't last long. The area around the injection site may turn red afterward.

POSSIBLE SIDE EFFECTS OF FULVESTRANT

Here, we explain the most common side effects of fulvestrant. You may experience some of the side effects mentioned here, though it is rare for a patient to have all of them. If you are taking other drugs, you may have certain side effects that are not listed here.

Always inform your doctor or nurse of the side effects you experience. They can prescribe drugs to help control them and can also give you advice on managing side effects.

NAUSEA, VOMITING, AND LOSS OF APPETITE

Let your doctor or nurse know if this happens. If it doesn't get better, your doctor may prescribe drugs to help control it. If you don't have much of an appetite, try to eat many small meals or snacks on a regular schedule.

INJECTION SITE

You may have some pain, redness, or swelling in the injection site. You may need to take simple painkillers. Let your doctor know if this becomes a problem.

TIREDNESS AND LACK OF ENERGY

When you start to take fulvestrant, you may feel tired, drowsy, or feel like you have no energy. Try to pace yourself until this improves. It is important to strike the correct balance between getting enough rest and staying physically active. Even taking short walks regularly will help you feel less tired. If you feel drowsy, don't drive or operate heavy machinery.

CHANGES IN THE LIVER

Fulvestrant can change the way the liver functions. It is very unlikely you will notice any problems, though your doctor will take periodic blood samples to check whether your liver is working properly.

HOT FLASHES AND SWEATING

These tend to be mild, though this can vary. Hot flashes can subside after the first few months. It can help to lower your intake of nicotine, alcohol, and hot beverages containing caffeine such as tea and coffee. Dress in layers so you can remove clothing if you need to. Natural fabrics such as cotton may be most comfortable.

Tell your doctor if your hot flashes become bothersome. Low doses of certain antidepressants can help reduce hot flashes.

DIARRHEA

This is normally mild. If this doesn't get better, your doctor can prescribe medicines to control your diarrhea. Make sure you drink at least two liters of fluids each day if you have diarrhea.

HEADACHES

Let your doctor or nurse know if you have headaches. Normally, this can be easily controlled with over-the-counter drugs.

ACHING OR PAIN IN THE JOINTS OR MUSCLES

You may have pain in your back, joints, or muscles. Let your doctor or nurse know if this happens. They can prescribe painkillers and give you advice.

SKIN RASHES

You may develop a mild rash. Let your doctor or nurse know if this happens. It is very important that you contact your doctor immediately if you develop a severe rash.

Less common side effects

Urinary infections

Let your doctor know if you have pain or discomfort when urinating, if you urinate more frequently than normal, or if your urine is cloudy or foul-smelling. Drink lots of fluids if you think you may have a urinary infection.

BLOOD CLOTS (Thrombosis)

Fulvestrant may slightly increase your chances of having a blood clot. A blood clot may cause symptoms such as pain, reddening or swelling in a leg, difficulty breathing, and pain in the chest. Get in touch with your doctor immediately if you have any of these symptoms. A blood clot is a serious matter, but your doctor can use drugs to thin your blood. Your doctor or nurse specialist can give you more information.

VAGINAL BLEEDING OR DISCHARGE

Sometimes, women may have some vaginal bleeding. This normally happens in the first weeks of treatment. It is a rare side effect and normally happens when changing to fulvestrant from another hormone therapy. If it continues for more than a few days, let your doctor or breast care nurse.

Another rare side effect is white vaginal discharge or yeast infection. Tell your doctor if this happens to you.

MORE INFORMATION ABOUT FULVESTRANT

DELAYING AN INJECTION

Occasionally delaying an injection by a day or two will not make much of a difference. However, it is important that you have your injections every month as prescribed.

HOSPITAL ADMISSION

If you are admitted to the hospital for any reason not related to cancer, it is important that you tell your doctors and nurses caring for you that you are receiving hormone treatment. OTHER DRUGS

Fulvestrant can interact with other drugs. This includes medications that can be purchased in a store or pharmacy. Tell your doctor if you are taking any drugs, including complementary therapies, and herbal remedies.

Because fulvestrant is given as an injection into the muscle, it should not be given to people who are taking anticoagulants such as warfarin.

MEDICAL OR DENTAL TREATMENT

If you have to go to the hospital for whatever reason other than cancer, always tell the doctors and nurses that you are taking fulvestrant. Explain to them that you are undergoing hormone therapy that no one should stop or restart if it is not done under the advice of a cancer doctor.

Always let your dentist know that you are taking fulvestrant.