What is Tamoxifen citrate?Tamoxifen, an anticancer drug, is given to treat breast cancer in women and men. It is used to lower the chance of breast cancer in women with a higher than normal chance of getting breast cancer in the next 5 years (high-risk women).
Tamoxifen is also used to treat breast cancer in women after they have finished early treatment. Early treatment can include surgery, radiation, and chemotherapy. Tamoxifen may keep the cancer from spreading to other parts of the body. It may reduce the chance of getting a new breast cancer.
In addition, tamoxifen is used to reduce the risk of breast cancer spreading in women who have ductal carcinoma in situ (DCIS) (breast cancer located in the milk ducts and which has not spread) and have already undergone breast cancer surgery and radiation therapy.
What is the most important information I should know about Tamoxifen citrate?Although tamoxifen reduces the risk of breast cancer, it may increase the possibility of developing endometrial (uterine) cancer. Women should notify their physician immediately if they develop abnormal vaginal bleeding, experience changes in vaginal discharge, or feel an increase in pelvic pain or pressure.
Tamoxifen may also cause other types of cancer in addition to uterine cancer.
Tamoxifen may cause women to develop noncancerous changes in their uterus. These include endometriosis, fibroids in the uterus, menstrual cycle irregularities, or the absence of menstrual periods.
Have regular gynecology checkups ("female exams"), breast exams, and mammograms. Your doctor will tell you how often. These will check for signs of breast cancer and cancer of the endometrium (lining of the uterus).
Tell all your doctors you see that you are taking tamoxifen.
Tamoxifen may increase the chances of developing a blood clot in the lung or in the leg.
Tamoxifen may increase the chance of developing liver cancer and liver abnormalities such as hepatitis.
Tamoxifen may cause eye problems. These include vision changes, damage to the retina of the eye, clots within the blood vessels of the eye, and cataracts.
Pay close attention to your body since Tamoxifen may cause serious side effects. Tell your doctor right away if you have any new breast lumps.
Tamoxifen may cause harm to the unborn baby if used during pregnancy. Women should not take tamoxifen if they are pregnant or planning to become pregnant. They should also not become pregnant for 2 months after they have stopped taking tamoxifen. Women who have not gone through menopause and are sexually active should use an effective nonhormonal contraceptive (e.g., condoms, diaphragm) while on tamoxifen and for 2 months after discontinuing tamoxifen.
Tamoxifen may affect components of your blood, including very low platelet counts (thrombocytopenia), very low white blood cell counts (leukopenia), and low neutrophil counts (neutropenia).
Who should not take Tamoxifen citrate?Do not take tamoxifen if you are allergic to it or any of its components.
Do not take tamoxifen if you are pregnant, planning to become pregnant, or are nursing.
Also, women who are on coumarin-type anticoagulant therapy (such as warfarin), have a history of deep vein thrombosis (such as a blood clot in the leg), or have a history of a blood clot developing in their lung should not take tamoxifen.
What should I tell my doctor before I take the first dose of Tamoxifen citrate?Tell your doctor about all prescription, over-the-counter, and herbal medications you are taking before beginning treatment with tamoxifen. Also, talk to your doctor about your complete medical history, especially if you are a woman who is on coumarin-type anticoagulant therapy (such as warfarin), has a history of deep vein thrombosis (such as a blood clot in your leg), or a pulmonary embolus (blood clot in your lung).
What is the usual dosage?The information below is based on the dosage guidelines your doctor uses. Depending on your condition and medical history, your doctor may prescribe a different regimen. Do not change the dosage or stop taking your medication without your doctor's approval.
Breast Cancer Treatment
The usual dosage ranges from 20-40 milligrams (mg) daily. If you are taking >20 mg a day, your doctor will have you divide the total into two smaller doses taken in the morning and evening.
Ductal Carcinoma in Situ
The usual dose is 20 mg daily for 5 years.
To Reduce the Incidence of Breast Cancer in High-Risk Women
The usual dose is 20 mg daily for 5 years.
How should I take Tamoxifen citrate?Swallow the tamoxifen tablet(s) whole, with water or another non-alcoholic liquid. You can take tamoxifen with or without food. Take your medicine every day. It may be easier to remember if you take it at the same time each day. Take tamoxifen tablets for 5 years, unless your doctor tells you otherwise.
What should I avoid while taking Tamoxifen citrate?Do not become pregnant while taking tamoxifen or for 2 months after you stop taking tamoxifen. Tamoxifen can prevent hormonal birth control methods (e.g., birth control pills, patches, injections, rings, and implants) from working. Therefore, while taking tamoxifen, use birth control methods that don't use hormones, such as condoms, diaphragms with spermicide, or plain intrauterine devices (IUDs). If you get pregnant, stop taking tamoxifen right away and call your doctor. Do not breastfeed if you are using tamoxifen.
What are possible food and drug interactions associated with Tamoxifen citrate?If tamoxifen is taken with certain other drugs, the effects of either could be increased, decreased, or altered. It is especially important to check with your doctor before combining tamoxifen with the following: aminoglutethimide, anastrazole, bromocriptine, coumarin-type anticoagulants (such as warfarin), letrozole, medroxyprogesterone, phenobarbital, and rifampin.
What are the possible side effects of Tamoxifen citrate?Side effects cannot be anticipated. If any develop or change in intensity, tell your doctor as soon as possible. Only your doctor can determine if it is safe for you to continue taking this drug.
Side effects may include: cataracts, changes in menstrual period, constipation, diarrhea, edema (swelling), fatigue, fluid retention, flushing, headache, hot flashes, high blood pressure, muscle pain, nausea, shortness of breath, vaginal discharge, vomiting, weight loss
Can I receive Tamoxifen citrate if I am pregnant or breastfeeding?Avoid taking tamoxifen if you are pregnant, planning to become pregnant, or are breastfeeding.
What should I do if I miss a dose of Tamoxifen citrate?If you miss a dose of tamoxifen, take it when you remember, then take the next dose as usual. If it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not take two doses at once.
How should I store Tamoxifen citrate?Store at room temperature in a tightly closed, light-resistant container.