Letrozole is a hormone therapy drug. It is used to treat breast cancer in women who have gone through menopause.

HOW DOES LETROZOLE 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 is called estrogen receptor-positive (ER-positive) breast cancer.

After menopause, estrogen is no longer made in the ovaries. Instead it's made in the fatty tissues of the body. This happens when an enzyme called aromatase changes other hormones into estrogen. Letrozole is a drug called an aromatase inhibitor. It blocks this process and reduces the amount of estrogen in the body.

WHEN IS LETROZOLE GIVEN?

Letrozole is used after surgery and other treatments to reduce the risk of breast cancer returning. It is normally taken over a number of years. Doctors sometimes prescribe it before or after another type of hormone therapy.

Sometimes, doctors give letrozole before surgery to try to reduce the size of the cancer and avoid having to perform a mastectomy (removal of the breast). Letrozole is also used to control breast cancer that has spread to other parts of the body (secondary breast cancer).

TAKING YOUR LETROZOLE TABLETS

Letrozole is taken once a day in tablet form. The pills are taken at the same time each day, either in the morning or at night. Always take the pills exactly as your nurse or pharmacist has told you. This is important to ensure that it is working as well as possible.

There are certain important things to remember when taking the tablets.

• If you forget to take a pill, take one as soon as you remember. Except when it is almost time for your next dose, do not take a double dose.
• Keep the pills in their original packaging at room temperature. They should be stored away from heat and direct sunlight.
• Keep them safe and out of the reach of children.
• Get a new prescription before the one you have runs out, and keep track of holidays, when pharmacies may be closed.
• Return the remaining pills to the hospital if the treatment is discontinued.

POSSIBLE SIDE EFFECTS OF LETROZOLE

Here, we explain the most common side effects of letrozole. 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. Do not stop taking letrozole unless your doctor instructs you to.

HOT FLASHES AND SWEATING

These are common and tend to be mild, though they can vary. Hot flashes and sweating 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.

BONE THINNING

Taking letrozole for a number of years increases the risk of bone thinning (osteoporosis). This may increase the risk of bone fractures. You will normally have a bone density scan to check on the healthiness of your bones before and during the treatment. If you are at risk of developing osteoporosis, your doctor may prescribe drugs called bisphosphonate to protect your bones. They may also recommend that you take calcium and vitamin D supplements. Taking regular walks, eating a healthy diet, not smoking, and following guidelines for drinking alcohol will also help strengthen your bones.

TIREDNESS AND LACK OF ENERGY

When you start to take letrozole, 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. Taking short walks regularly will help you feel less tired. If you feel drowsy, don't drive or operate heavy machinery.

ACHING OR PAIN IN THE JOINTS AND MUSCLES

You may have pain or stiffness in the joints, or sometimes in your muscles. Let your doctor or nurse know if this happens. They can prescribe painkillers and give you advice. Physical activity and maintaining a healthy weight can help reduce joint pain and keep joints flexible. Tell your doctor if this does not get better.

NAUSEA, INDIGESTION, AND ABDOMINAL PAIN

Nausea is usually mild, but tell your doctor or nurse if this happens. Letrozole can also cause indigestion or abdominal pain. Let your health professionals know if you have any of these symptoms. They can give you drugs to help.

CHANGES IN APPETITE

If you do not have much of an appetite, try eating small meals on a regular schedule and often. If your eating problems do not improve, talk to your doctor or nurse.

Some women find that their appetite increases. Healthy eating and staying physically active will help if you have worries about your weight.

HAIR THINNING

Some women notice that their hair thins out while they are taking letrozole. This is normally mild. Your hair will thicken after the treatment ends.

SKIN RASHES

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

MOOD AND BEHAVIOR CHANGES

Some women may discover that they feel down when taking letrozole. Or they may have difficulty concentrating or may feel anxious or have trouble sleeping. Talk to your nurse or doctor if you experience these changes so that they can give you support and

HEADACHES

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

DIZZINESS

Letrozole may cause dizziness. Tell your doctor or nurse if this is a problem.

WEIGHT GAIN

You may gain weight when taking hormone therapy. Eating healthy meals and becoming more physically active can help you maintain a healthy weight. Your nurse can give you further advice on this.

VAGINAL BLEEDING

In rare cases, women may have vaginal bleeding. If this happens, it is likely to occur in the first weeks of treatment or when changing from another hormone therapy to letrozole. If your vaginal bleeding continues for more than a few days, tell your doctor or nurse.

HIGH BLOOD PRESSURE

Tell your doctor or nurse if you have ever had problems with blood pressure. Your nurse will monitor it regularly during treatment.

HIGH CHOLESTEROL

Your doctor may check your cholesterol levels with a blood test.

FLUID BUILD-UP

Your ankles and feel may swell up because of the build-up of fluid. Tell your doctor if you notice this or any other type of swelling.

LESS COMMON SIDE EFFECTS

VAGINAL DRYNESS

Non-hormonal creams and gels or lubricants can help reduce vaginal dryness and discomfort during sex.

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 an infection.

EYE PROBLEMS

Sometimes, women have irritated eyes or blurred vision when taking letrozole. Always tell your doctor or nurse about any change to your eyesight.

CHANGES TO YOUR HEARTBEAT

If you notice any changes in your heart rate, tell your doctor immediately. If you have pain or pressure in your chest or feel out of breath at any time during or after treatment, let your doctor know immediately.

MORE INFORMATION ABOUT LETROZOLE

IF YOU HAVE PROBLEMS

Most side effects settle down a few months after taking letrozole or can be controlled or managed. However, they may be more problematic for some women. If this is the case, make sure you talk to your cancer doctor or nurse. They can normally suggest ways to improve the side effects.

It is very important that you do not stop taking letrozole without telling your doctor, as this may affect the success of the treatment. It the side effects are very bothersome and are unmanageable, your oncologist may suggest you start on a different hormone therapy.

OTHER DRUGS

Letrozole 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 other medication. These include complementary therapies and herbal remedies.

MEDICAL AND 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 letrozole. Explain that you are taking hormone therapy and that no one should start or stop it without taking to your cancer specialist in the first place.

Always let your dentist know that you are taking letrozole.