Exemestane

What is Exemestane?

Exemestane is a prescription medicine used to treat certain breast cancers. It belongs to a drug class called aromatase inactivators (also called steroidal aromatase inhibitors), a type of hormone (endocrine) therapy. It was first sold under the brand name Aromasin, and generic versions are widely available.

Approved uses: In the United States, exemestane is approved for postmenopausal women with:

• Early breast cancer: Adjuvant treatment of estrogen receptor-positive early breast cancer after 2 to 3 years of tamoxifen, to complete a total of 5 consecutive years of hormone therapy
• Advanced breast cancer: Treatment of advanced breast cancer that has grown after tamoxifen therapy

Formulation and strength: Exemestane is taken by mouth as a 25 mg tablet. Other uses should be discussed only with your doctor.

What is the Recommended Dosage of Exemestane?

Your dose is set by your oncologist and should always follow their instructions and your pharmacy label. Exemestane is a tablet swallowed whole, usually once a day after a meal at about the same time each day. Your care team will tell you how long to take it. Treatment often lasts several years.

Your care team may adjust the dose or schedule based on:

• Your condition: The length of treatment depends on the cancer type, stage, and your response.
• Other medicines: Some medicines can lower exemestane levels, and a higher dose may be used in certain cases.
• Liver and kidney function: No routine dose change is needed for mild to moderate problems, but your team will watch you closely.
• Overall health: Age and other conditions can matter.

Do not change, skip, or stop doses on your own, even if you feel well.

How Exemestane Works

Some breast cancers grow in response to the hormone estrogen. After menopause, most estrogen is made when an enzyme called aromatase changes other hormones into estrogen in fat, muscle, and other tissues.

Exemestane binds to aromatase and permanently turns it off, which lowers estrogen levels in the body. With less estrogen, hormone-sensitive breast cancer cells may grow more slowly or be less likely to return. Exemestane is used to control the disease or lower the chance of it coming back, and it is not considered a cure. Regular exams, imaging, and follow-up visits are an important part of care.

Is a Prescription Required to Buy Exemestane Online?

Yes. Exemestane is prescription-only. It should be prescribed and monitored by a licensed medical oncologist (a cancer specialist), often a breast cancer specialist, who may work with a breast surgeon or other members of your care team.

• Tests on the tumor are needed to confirm that it is hormone receptor-positive.
• Buy only from a licensed pharmacy that requires a valid prescription.
• Counterfeit or substandard medicines exist. Be cautious of websites that sell without a prescription or ship from unclear sources.
• Check that the tablets match what your pharmacist describes, and ask your pharmacist if packaging or appearance looks different.

Side Effects of Exemestane

Not everyone gets every side effect. Many can be managed with help from your care team.

Common Side Effects

• Hot flashes and increased sweating
• Joint pain, stiffness, or muscle aches
• Tiredness
• Trouble sleeping
• Headache or dizziness
• Nausea
• Hair thinning
• Increased appetite or weight gain
• Mood changes or depression
• Swelling in the hands or feet
• Changes in liver blood tests

Serious Side Effects

These are less common but need prompt attention:

• Bone loss and fractures: exemestane can lower bone density over time, which may lead to osteoporosis or broken bones
• Heart and blood vessel problems: chest pain, shortness of breath, or signs of a heart attack or stroke
• Severe allergic reaction: swelling of the face, lips, or throat, trouble breathing, or widespread rash
• Liver problems: yellowing of the skin or eyes, dark urine, severe stomach pain, or unusual tiredness
• Nerve problems: numbness, tingling, or pain in the hands (carpal tunnel syndrome has been reported)
• Low vitamin D or other changes found on blood tests

Seek immediate medical care if you have chest pain, trouble breathing, signs of stroke, or swelling of the face or throat. Contact your oncology team promptly for severe bone or joint pain, a fracture, vaginal bleeding, or any symptom that worries you.

Drug Interactions

Tell your oncologist and pharmacist about everything you take, including prescription drugs, over-the-counter (OTC) products, vitamins, supplements, and herbal products. Major categories include:

• Strong CYP3A4 inducers (such as rifampin, phenytoin, carbamazepine) can lower exemestane levels and may make it less effective. Your doctor may adjust the dose.
• St. John’s wort: This herbal product can lower exemestane levels and should be avoided unless your care team says otherwise.
• Estrogen-containing products: Hormone replacement therapy, estrogen creams or patches, and some birth control products may work against exemestane.
• Other cancer medicines: Your oncologist will decide if and how exemestane is combined with other treatments, such as everolimus.
• Calcium and vitamin D: These are often recommended for bone health, but ask your care team what is right for you.

Bring a complete, updated medication list to every appointment.

Safety & Important Considerations

• Bone health: A bone density scan is often done before treatment and repeated as advised. Your team may recommend calcium, vitamin D, weight-bearing exercise, or bone-strengthening medicine.
• Heart health: Tell your team about any heart disease, high blood pressure, or high cholesterol.
• Liver disease: Liver blood tests may be checked during treatment. Discuss any liver problems with your specialist.
• Kidney disease: Little change is expected for most kidney problems. Discuss severe kidney disease with your specialist.
• Menopausal status: Exemestane is approved only for postmenopausal women. If there is any doubt about menopausal status, your team may check hormone levels.
• Vitamin D: Vitamin D levels may be checked before treatment, since low levels are common.
• Pregnancy: Exemestane can harm an unborn baby. It is not for use during pregnancy. Women who could become pregnant may need a pregnancy test before treatment and effective contraception during treatment and for a period after the last dose. Tell your oncologist right away if you are or may become pregnant.
• Breastfeeding: Breastfeeding is not recommended during treatment and for a period after the last dose.
• Dizziness and tiredness: Use caution when driving or using machines until you know how exemestane affects you.
• Older adults and children: Older adults take the same dose but are monitored for bone and heart health. Exemestane is not approved for use in children.
• Monitoring: Expect regular visits, breast exams, imaging, and blood tests.

Who This Medication Is For

Exemestane is intended for postmenopausal women with estrogen receptor-positive breast cancer, either early-stage cancer after tamoxifen or advanced cancer that has grown after tamoxifen, as decided by their oncology team. Treatment plans differ from person to person.

Who Should Not Take Exemestane

Exemestane should not be used by people with a known severe allergic reaction to exemestane or any ingredient in the tablet. In some other countries, pregnancy, breastfeeding, and being premenopausal are also listed as reasons not to use it.

Discuss with your oncologist before starting if you:

• Have had an allergic reaction to exemestane or any tablet ingredient
• Are premenopausal, pregnant, planning pregnancy, or breastfeeding
• Have osteoporosis or a high risk of broken bones
• Have heart disease, high blood pressure, or high cholesterol
• Have liver disease or severe kidney disease
• Take medicines that interact with exemestane, such as strong enzyme inducers or estrogen products

What to Do If You Miss a Dose

• Take the missed dose as soon as you remember, unless it is almost time for your next dose. In that case, skip the missed dose and continue with your regular schedule.
• Never take two doses at once to make up for a missed one.
• If you are unsure what to do, or you miss several doses, contact your oncology team or pharmacist.

Related medications to Exemestane

Other medicines are used for hormone receptor-positive breast cancer, depending on the cancer’s stage and features, your menopausal status, and your health:

• Other aromatase inhibitors: anastrozole and letrozole
• Other hormone-based treatments: tamoxifen, fulvestrant, and newer oral hormone therapies
• Combination approaches: hormone therapy together with targeted medicines such as CDK4/6 inhibitors or everolimus in selected cases
• Other approaches: chemotherapy, surgery, and radiation

These medicines differ in side effects, interactions, and approved uses. Switching or combining treatments must be decided together with your oncologist.

Storage Instructions

• Store at room temperature, about 68°F to 77°F (20°C to 25°C), with brief trips between 59°F and 86°F (15°C to 30°C) allowed.
• Keep tablets in the original container with the lid tightly closed, away from moisture (not in the bathroom) and light.
• Keep out of reach of children and pets.
• Do not use tablets past the expiration date. Ask your pharmacist about safe disposal of unused medicine.
• Caregivers who are pregnant or planning pregnancy should ask the care team about handling precautions and should avoid handling crushed or broken tablets.

Disclaimer:

This page is for educational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. Patients must consult a licensed medical oncologist before starting, changing, or stopping treatment. Treatment decisions must be based on a full clinical evaluation by a qualified specialist.