What is Aromasin

Aromasin is a brand name of a drug called exemestane. Just like Arimidex (anastrozole), Aromasin (exemestane) is also used to treat early breast cancer in postmenopausal women and who have already been treated with a medication called tamoxifen (Nolvadex) for 2 to 3 years. Aromasin (exemestane) is also used to treat breast cancer in women who have experienced menopause whose breast cancer has worsened while they were taking tamoxifen. Aromasin (exemestane) is in a class of medications called aromatase inhibitors. It works by decreasing the amount of estrogen produced by the body. This can slow or stop the growth of some breast tumors that need estrogen to grow.

Aromasin (exemestane) was approved for use in postmenopausal women with estrogen receptor positive breast cancer in the United States in 1999. Exemestane is available in 25 mg tablets in generic forms and under the brand name Aromasin. Current indications are as adjuvant therapy in postmenopausal women with estrogen sensitive breast cancer after failure, intolerance or as replacement of tamoxifen.

Aromasin (exemestane) is a steroidal inhibitor of aromatase which effectively blocks estrogen synthesis in postmenopausal women and is used as therapy of estrogen receptor positive breast cancer, usually after resection and after failure of tamoxifen. Aromatase is the enzyme responsible for the conversion of testosterone to estrone (E1) and of androstenedione to estradiol (E2). Highest levels of aromatase are found in the ovary and placenta, which are the major sources of estrogen in premenopausal women. However, aromatase is also found in other tissues, such as liver, kidney, adrenals, brain, muscle and subcutaneous fat where it is also active in producing estrogens, although at low levels. These tissues are the major source of estrogen in postmenopausal women. Inhibitors of aromatase were developed to block the synthesis of estrogen in the peripheral tissues and, thus, as antiestrogen therapy of estrogen receptor positive breast cancer in postmenopausal women. Exemestane is a steroidal, specific aromatase inhibitor which has little or no effect on adrenal glucocorticoid or mineralocorticoid synthesis.

Exemestane is given in doses of 25 mg once daily by mouth for up to five years.

Aromasin (exemestane) common side effects include hot flashes, night sweats, arthralgias, fatigue, dizziness, nervousness, insomnia, nausea, weight gain and headache. Uncommon, but potentially severe adverse reactions include reduction in body mineral density and embryo-fetal toxicity.

Tamoxifen vs Aromasin

Tamoxifen is a nonsteroidal antiestrogen that is widely used in the treatment and prevention of breast cancer.

Tamoxifen is selective estrogen receptor modulator (SERM). This means that Tamoxifen acts against (or block) estrogen (a female hormone) in some tissues of the body, but act like estrogen in others. Estrogen can fuel the growth of breast cancer cells. Tamoxifen blocks estrogen in breast cells, which is why Tamoxifen can be useful in lowering breast cancer risk. Other benefits of tamoxifen is the prevention of osteoporosis, a severe weakening of the bones that is more common after menopause.

Tamoxifen is used mainly to treat hormone receptor-positive breast cancer (breast cancer with cells that have estrogen and/or progesterone receptors on them).

To lower the risk of breast cancer, tamoxifen is taken for 5 years. Tamoxifen is taken once a day. Tamoxifen also comes in a liquid form. Tamoxifen can be taken whether or not you have gone through menopause.

The effect of tamoxifen on breast cancer risk has varied in different studies. When the results of all the studies are taken together, the overall reduction in risk for Tamoxifen is about 40% (more than a third). Tamoxifen lowers the risk of both invasive breast cancer and ductal carcinoma in situ (DCIS).

Tamoxifen side effects

Menopausal symptoms

The most common side effects of these tamoxifen are symptoms of menopause. These include hot flashes and night sweats. Tamoxifen can also cause vaginal dryness and vaginal discharge. Pre-menopausal women taking tamoxifen can experience menstrual changes. Menstrual periods can become irregular or even stop. Although periods often start again after the drug is stopped, they don’t always, and some women go into menopause. This is more likely in women who were close to menopause when they started taking the drug.

Other more serious side effects are rare. These include serious blood clots and cancer of the uterus.

Blood clots

Tamoxifen increases your risk of developing blood clots in a vein in your leg (deep venous thrombosis) or in your lungs (pulmonary embolism). These clots can sometimes cause serious problems, and even death. In the major studies looking at tamoxifen for breast cancer prevention, the overall risk of these blood clots over 5 years of treatment was less than 1%. This risk could be higher if you had a serious blood clot in the past, so these drugs are generally not recommended to lower breast cancer risk for anyone with a history of blood clots.

Because tamoxifen increases your risk of developing serious blood clots, there is also concern that it might also increase your risk of heart attack or stroke, although this is not clear. This is something you might want to discuss with your doctor, especially if you have a history of a heart attack or stroke, or if you are at increased risk for them.

Cancer of the uterus

Because tamoxifen acts like estrogen in the uterus, it can increase your risk of endometrial cancer and uterine sarcoma (cancers of the uterus). Tamoxifen also is linked to a higher risk of endometrial pre-cancers.

Although tamoxifen does increase the risk of uterine cancer, the overall increase in risk is low (less than 1%). The risk of uterine cancer goes back to normal within a few years of stopping the drug.

The increased risk seems to affect women over 50, but not younger women.

If you have been diagnosed with uterine cancer or pre-cancer you should not take tamoxifen.

If you have had a hysterectomy (surgery to remove the uterus), you are not at risk for endometrial cancer or uterine sarcoma and do not have to worry about these cancers.

If you are taking tamoxifen, tell your doctor if you have any abnormal vaginal bleeding or spotting, especially after menopause, as these are possible symptoms of uterine cancer.

What is Aromasin used for?

Aromasin (exemestane) is used to treat early estrogen receptor-positive (or ER+) breast cancer. Aromasin (exemestane) is also used for first-line treatment of estrogen receptor-positive or estrogen receptor-unknown advanced or metastatic (cancer that has spread) breast cancer. Aromasin (exemestane) is also used to treat advanced breast cancer that has grown or spread after tamoxifen treatment. Aromasin (exemestane) is used only in women who have already stopped menstruating (postmenopausal).

Many breast cancer tumors grow in response to estrogen. Aromasin (exemestane) interferes with the production of estrogen in the body. As a result, the amount of estrogen that the tumor is exposed to is reduced, limiting the growth of the tumor.

Aromasin (exemestane) is also sometimes used to prevent breast cancer in women who are at high risk of developing the disease. Talk to your doctor about the risks of using Aromasin (exemestane) for your condition.

Aromasin special precautions

It is very important that your doctor check your progress at regular visits to make sure that Aromasin (exemestane) is working properly. Blood tests may be needed to check for unwanted effects.

It is unlikely that a postmenopausal woman may become pregnant. But, you should know that using Aromasin (exemestane) while you are pregnant could harm your unborn baby. Use an effective form of birth control during treatment with Aromasin (exemestane) and for at least 3 weeks after the last dose. If you think you have become pregnant while using Aromasin (exemestane), tell your doctor right away.

Do not use Aromasin (exemestane) together with tamoxifen (Nolvadex®, Soltamox®).

This medicine may cause serious allergic reactions, including anaphylaxis and angioedema, which can be life-threatening and require immediate medical attention. Call your doctor right away if you have itching, hives, hoarseness, trouble breathing or swallowing, or any swelling of your hands, face, or mouth while you are using Aromasin (exemestane).

Check with your doctor right away if you start having chest pains or difficulty with breathing. This medicine may increase the chance of heart problems, including heart attack, in women who have a history of ischemic heart disease.

This medicine may decrease bone mineral density when used for a long time. A low bone mineral density can cause weak bones or osteoporosis. If you have any questions about this, talk to your doctor.

This medicine may increase your cholesterol or fat in the blood. If this happens, your doctor may give you medicine to lower the cholesterol and fat.

Do not take Aromasin if you are also using medicines that contain estrogen (eg, Premarin®), birth control pills or patches, or other medicines used for hormone replacement therapy.

Do not take other medicines unless they have been discussed with your doctor. This includes prescription or nonprescription (over-the-counter [OTC]) medicines for appetite control, asthma, colds, cough, hay fever, or sinus problems, and herbal (e.g., St. John’s wort) or vitamin supplements.

Before taking Aromasin (exemestane):

  • tell your doctor and pharmacist if you are allergic to exemestane or any other medications.
  • tell your doctor and pharmacist what other prescription and nonprescription medications, vitamins, and nutritional supplements you are taking or plan to take. Be sure to mention any of the following: carbamazepine (Carbatrol, Epitol, Tegretol); medications that contain estrogen such as hormone replacement therapy and hormonal contraceptives (birth control pills, patches, rings, and injections); phenobarbital; phenytoin (Dilantin); and rifampin (Rifadin, in Rifater, in Rifamate). Your doctor may need to change the doses of your medications or monitor you carefully for side effects.
  • tell your doctor what herbal products you are taking, especially St John’s wort.
  • tell your doctor if you have or have ever had osteoporosis (condition in which the bones are fragile and break easily), liver or kidney disease.
  • tell your doctor if you are pregnant or plan to become pregnant. You will need to have a negative pregnancy test within 7 days before you begin to take exemestane. You should use birth control to avoid pregnancy during your treatment with exemestane and for 1 month after your final dose. If you become pregnant while taking exemestane, call your doctor immediately. Exemestane may harm the fetus.
  • tell your doctor if you are breastfeeding. You should not breastfeed during your treatment with exemestane and for 1 month after your final dose.

Aromasin drug Interactions

Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking this medicine, it is especially important that your healthcare professional know if you are taking any of the medicines listed below. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.

Using Aromasin with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.

  • Carbamazepine
  • Enzalutamide
  • Fosphenytoin
  • Mitotane
  • Phenytoin
  • Primidone
  • Rifabutin
  • Rifampin
  • Rifapentine
  • St John’s Wort

Other Interactions

Certain medicines should not be used at or around the time of eating food or eating certain types of food since interactions may occur. Using alcohol or tobacco with certain medicines may also cause interactions to occur. Discuss with your healthcare professional the use of your medicine with food, alcohol, or tobacco.
Other Medical Problems

The presence of other medical problems may affect the use of this medicine. Make sure you tell your doctor if you have any other medical problems, especially:

  • Bone marrow problems (e.g., lymphocytopenia) or
  • Bone problems (e.g., osteoporosis, broken bones)—Use with caution. May make these conditions worse.

Aromasin dosage

The dose of Aromasin will be different for different patients. Follow your doctor’s orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.

The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.

For oral dosage form (tablets):

  • For breast cancer in postmenopausal women:
    • Adults—25 milligrams (mg) once a day.
    • Children—Use is not recommended.

What should I do if I forget a dose?

Take the missed dose as soon as you remember it. However, if it is almost time for the next dose, skip the missed dose and continue your regular dosing schedule. Do not take a double dose to make up for a missed one.

Aromasin side effects

Aromasin (exemestane) may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:

  • hot flushes
  • sweating
  • muscle or joint pain
  • tiredness
  • headache
  • dizziness
  • feeling worried or anxious
  • depression
  • difficulty falling asleep or staying asleep
  • nausea
  • vomiting
  • increased appetite
  • diarrhea
  • hair loss
  • red, itchy skin
  • changes in vision
  • swelling of the arms, hands, feet, ankles, or lower legs

Some side effects can be serious. If you experience any of these symptoms, call your doctor immediately:

  • shortness of breath
  • chest pain

Your bone mineral density (BMD; a measure of the strength of the bones) may decrease while you are taking exemestane. This may increase the chance that you will develop osteoporosis (condition in which the bones are fragile and break easily). Talk to your doctor about the risks of taking exemestane.

Aromasin (exemestane) may cause other side effects. Call your doctor if you have any unusual problems while taking Aromasin.