Aromatase inhibitors

To try to:

• Stop a new estrogen receptor positive (ER+) breast cancer from developing OR
• Stop your ER+ breast cancer from returning
• Shrink your ER+ breast cancer and stop it from spreading to other parts of the body.

Letrozole (Femara®), anastrozole (Arimidex®), and exemestane (Aromasin®) are three different aromatase inhibitors that may be prescribed.

Aromatase inhibitors do not block estrogen from being made in the ovaries of women who have menstrual periods. If you have had a menstrual period in the past year, you will need to get an injection every 4 weeks to stop your periods OR need surgery to remove your ovaries.

Aromatase inhibitors are pills you take once a day with or without food. If you miss a pill, do not take 2 pills at the next dose.

Hot flashes

• You may sweat, feel warm and have flushing of the face.
• Wear light clothes and avoid alcohol, caffeine, and sugar to reduce symptoms.
• Exercise helps reduce these symptoms.

Joint stiffness and aches

• 1 out of 3 women will have pain and body aches.
• Acetaminophen or ibuprofen can help with stiffness and joint pain.
• Exercise helps to reduce these symptoms.

Bone thinning

• Bone density decreases on these medications.
• Low bone density raises your risk of breaking a bone in the future.
• It is important to take in enough calcium (1200 mg) and vitamin D (1,000 - 2,000 IU) every day to reduce bone loss. This can be taken through your diet and/or supplements.
• Weight-bearing exercise and medications help maintain bone density.
• Your doctor may order a test to check your bone density.

Vaginal dryness

• Vaginal moisturizers can treat and prevent vaginal dryness.
• Lubricants can help make you more comfortable during sex.

Some natural health products contain estrogen and should not be used with estrogen-lowering medications. Speak with a pharmacist and/or your doctor before you take other prescription medications, supplements, or natural health products.

Severe side effects are rare with aromatase inhibitors. If you are worried that your symptoms might be caused by this medication, stop taking it and tell your nurse or doctor right away.

If your symptoms are caused by your aromatase inhibitor another medication can be prescribed.

Approximately 80 per cent of breast cancers have 'estrogen receptors' (ER) on the cancer cells. These ER+ cancers are fed by the female hormone estrogen, which attaches to the ER. Estrogen can be made anywhere in the body by the enzyme aromatase from hormones called androgens. Aromatase inhibitors block aromatase (except in the ovaries of women who are still having menstrual periods) and this stops the body from making estrogen. This can help stop ER+ cancers from growing.