Tamoxifen is used for treating breast cancer that has spread to other sites in the body. It is also used along with other medicines to treat other types of breast cancer. It is used in women who are at high risk of breast cancer and in women with DCIS (after surgery and radiation) to decrease the risk of developing breast cancer. It may also be used for other conditions as determined by your doctor.
How to use
Use Tamoxifen as directed by your doctor. Check the label on the medicine for exact dosing instructions.
Tamoxifen comes with an extra patient information sheet called a Medication Guide. Read it carefully. Read it again each time you get Tamoxifen refilled.
Tamoxifen may be taken by mouth with or without food.
Take Tamoxifen with water or another nonalcoholic liquid.
Swallow this medication whole. Do not break, crush, or chew before swallowing.
Continue taking Tamoxifen even if you feel well. Do not miss any doses. Take Tamoxifen at the same time each day.
Drug Class and Mechanism
Tamoxifen is an antiestrogen. It works by blocking the effect of estrogen on certain tumors. This may prevent the growth of tumors that are activated by estrogen.
If you miss a dose of Tamoxifen, take it as soon as possible. If it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not take 2 doses at once.
Store Tamoxifen between 68 and 77 degrees F (20 and 25 degrees C) in a tightly closed, light-resistant container. Store away from moisture, heat, and light. Do not store in the bathroom. Do not take tablets after the expiration date printed on the label. Keep Tamoxifen out of the reach of children and away from pets.
Do NOT use Tamoxifen if:
you are allergic to any ingredient in Tamoxifen
you are using Tamoxifen to reduce your risk of breast cancer and you have a history of blood clots in the lung or leg
you are using Tamoxifen to reduce your risk of breast cancer and you also take certain anticoagulants (eg, warfarin)
you are taking anastrozole
Some medical conditions may interact with Tamoxifen . Tell your doctor or pharmacist if you have any medical conditions, especially if any of the following apply to you:
if you are pregnant, planning to become pregnant, or are breast-feeding
if you are taking any prescription or nonprescription medicine, herbal preparation, or dietary supplement
if you have allergies to medicines, foods, or other substances
if you have a history of blood clots in the legs or lungs
if you have high levels of calcium in your blood, a weakened immune system, or low levels of white blood cells or platelets in your blood
if you have high cholesterol or lipid levels
if you have cataracts or other vision problems
if you are using cytotoxic cancer medicines
if you are confined to a bed or chair
Possible Side Effects
All medicines may cause side effects, but many people have no, or minor side effects. Check with your doctor if any of these most COMMON side effects persist or become bothersome:
bone pain; constipation; coughing; hot flashes; muscle pain; nausea; tiredness; vaginal discharge; weight loss.
Seek medical attention right away if any of these SEVERE side effects occur:
Severe allergic reactions (rash; hives; itching; difficulty breathing; tightness in the chest; swelling of the mouth, face, lips, or tongue; unexplained hoarseness); abnormal menstrual periods; abnormal vaginal bleeding or bloody discharge; chest pain; coughing up blood; dark urine; decreased sexual desire or ability; depression; fever, chills, or persistent sore throat; groin or pelvic pain or pressure; loss of appetite; loss of balance or coordination; missed menstrual period; new or increased breast tumor or pain; new or unusual lumps; one-sided weakness; pain or swelling in one or both legs; red, swollen, blistered, or peeling skin; severe or persistent tiredness or weakness; shortness of breath; skin changes; stomach pain; sudden severe headache; swelling of the arms or the legs; unusual bleeding or bruising; vision or speech problems; yellowing of the eyes or skin.
If you have any questions about Tamoxifen , please talk with your doctor, pharmacist, or other health care provider.
Tamoxifen is to be used only by the patient for whom it is prescribed. Do not share it with other people.
If your symptoms do not improve or if they become worse, check with your doctor.