Tamoxifen

Generic name: Tamoxifen

Drug class: Hormones / antineoplastics, Selective estrogen receptor modulators

Dosage forms: Solution, Tablet

Root of administration: Oral

Dose: 10 mg/5 mL, 10, 20 mg

Mechanism of action: Tamoxifen blocks the actions of estrogen, a female hormone. Certain types of breast cancer require estrogen to grow.

Drug usage cases: Tamoxifen is used to treat some types of breast cancer in men and women. Tamoxifen is also used to lower a woman’s chance of developing breast cancer if she has a high risk (such as a family history of breast cancer).

Drug contra indications: You should not use tamoxifen if you are allergic to it. You should not use tamoxifen to reduce your risk of breast cancer if you also take warfarin (Coumadin, Jantoven). To make sure tamoxifen is safe for you, tell your doctor if you have:

a stroke or blood clot; liver disease; high cholesterol or triglycerides (a type of fat in the blood); cataracts; chemotherapy; or if you also use anastrozole or letrozole. Taking tamoxifen may increase your risk of uterine cancer, liver cancer, stroke, or a blood clot in the lung, which can be fatal. Talk with your doctor about your own risks. This medicine is not approved for use by anyone younger than 18 years old.

Side effects: Get emergency medical help if you have signs of an allergic reaction to tamoxifen: hives; difficulty breathing; swelling of your face, lips, tongue, or throat. Tamoxifen can increase your risk of stroke or blood clots. Call your doctor at once if you have:

signs of a stroke – sudden numbness or weakness, severe headache, slurred speech, problems with vision or balance; signs of a blood clot in the lung – chest pain, sudden cough or shortness of breath, dizziness, coughing up blood; or signs of a blood clot deep in the body – pain, swelling, or warmth in one leg. Also call your doctor at once if you have:

unusual vaginal bleeding or discharge; blurred vision, eye pain or redness, seeing halos around lights; changes in your menstrual periods; pain or pressure in your pelvic area; a new breast lump; liver problems – nausea, upper stomach pain, itching, tired feeling, loss of appetite, dark urine, clay-colored stools, jaundice (yellowing of the skin or eyes); or high blood calcium – confusion, tiredness, nausea, vomiting, loss of appetite, constipation, increased thirst or urination, weight loss.

Warnings: Taking tamoxifen may increase your risk of uterine cancer, liver cancer, stroke, or a blood clot in the lung, which can be fatal. You should not use tamoxifen if you are allergic to it, if you have a history of blood clots in your veins or your lungs, or if you are taking a blood thinner such as warfarin (Coumadin). Before using this medicine, tell your doctor if you have liver disease, high triglycerides (a type of fat in the blood), a history of cataract, or a history of stroke or blood clot. Also tell your doctor if you if you are receiving chemotherapy or radiation treatment. If you are taking tamoxifen to reduce your risk of breast cancer, you may need to take your first dose while you are having a menstrual period. You may also need to have a pregnancy test before you start taking this medicine, to make sure you are not pregnant. Follow your doctor’s instructions. To make sure this medication is not causing harmful effects, your doctor may want you to have mammograms and to perform routine breast self-exams on a regular basis. Your liver function may also need to be tested. Visit your doctor regularly.

Use during pregnancy or breastfeeding: Do not use tamoxifen if you are pregnant. It could harm the unborn baby. You may need a pregnancy test to make sure you are not pregnant. Tell your doctor if you become pregnant. To prevent pregnancy while using tamoxifen, use a barrier form of birth control: condom, diaphragm, cervical cap, or contraceptive sponge while you are using this medication and for at least 2 months after your treatment ends. Avoid using hormonal birth control, including birth control pills, injections, implants, skin patches, and vaginal rings. Do not breastfeed while using tamoxifen, and for at least 3 months after your last dose.