- Type of Drug: Antiestrogen.
- Prescribed for: Breast cancer in women. When used together with chemotherapy after mastectomy surgery, Tamoxifen is effective in delaying the recurrence of surgically curable cancers in postmenopausal women or women over age 50. It has been used in the prevention of breast cancer among high-risk women who have no current signs of the disease. Tamoxifen has also been prescribed to treat painful breasts and to decrease swollen painful breasts in men. It may also be used in the treatment of male breast cancer and in pancreatic cancer.
Tamoxifen Citrate General Information
Tamoxifen is effective against breast cancer in women whose tumors are tested and found to be estrogen-positive. It works by competing with the sites in tissues to which estrogens attach. Once Tamoxifen binds to an estrogen receptor, it disrupts the cell in the same way that an estrogen would and prevents the cancer cell from dividing; Of those women whose breast cancer has spread to other parts of their bodies, 50 to 60 percent may benefit from taking Tamoxifen.
Another medicine, Anastrozole (Arimidex) can be given to postmenopausal women with advanced breast cancer who don’t respond to Tamoxifen. Anastrozole is the first of a new drug type (aromatase inhibitors) that reduces estrogen production in your body.
Tamoxifen Citrate Cautions and Warnings
Visual difficulty has occurred in patients taking Tamoxifen for 1 year or more in doses at least 4 times above the maximum recommended dosage. A few cases of decreased visual clarity and other eye side effects have been reported at normal doses.
People taking Tamoxifen have experienced liver inflammation and, rarely, other more serious liver abnormalities.
Animal studies have shown that very high doses of this drug (15 mg per pound of body weight) may cause liver cancer.
Tamoxifen Citrate Possible Side Effects
Side effects are usually mild.
- Most common: hot flashes, nausea, and vomiting (up to 25 percent of all patients).
- Less common: vaginal bleeding or discharge, irregular periods, and skin rash.
- Rare: high blood-calcium levels, swelling of the arms or legs, changes in sense of taste, vaginal itch, depression, dizziness, light-headedness, headache, visual difficulty, and reduced white-blood-cell count or reduced platelet count. Ovarian cysts have occurred in premenopausal women with advanced breast cancer who have taken Tamoxifen. Increases in tumor pain and local disease sometimes follow a good response with Tamoxifen.
- The effects of Warfarin and other anticoagulant (blood-thinning) drugs may be increased by Tamoxifen. Tamoxifen may increase blood-calcium levels.
- Bromocriptine may increase the amount of Tamoxifen in the bloodstream.
Tamoxifen is best taken on an empty stomach but may be taken with food or milk if it upsets your stomach.
10 to 20 mg morning and evening.
Tamoxifen Citrate Overdosage
Overdose may lead to breathing difficulty or convulsions. Other symptoms are tremors, overactive reflexes, dizziness, and unsteadiness. Overdose victims should be taken to a hospital emergency room for treatment. ALWAYS bring the prescription bottle.
Take this medicine according to your doctor’s directions. Tell your doctor if you become very weak or sleepy, or if you experience confusion, pain, or swelling of your legs, difficulty breathing, blurred vision, bone pain, hot flashes, nausea, vomiting, weight gain, irregular periods, dizziness, headache, or loss of appetite while taking this drug. If you vomit shortly after taking a dose of Tamoxifen, your doctor may tell you to take another dose or wait until the next dose.
Women taking Tamoxifen should use effective contraception until treatment is complete.
If you forget to take a dose of Tamoxifen, skip the forgotten dose, call your doctor, and continue your regular dosing schedule. Do not take a double dose.
Tamoxifen Citrate Special Populations
Because of its antiestrogen effects, Tamoxifen can harm a developing fetus. Although there are no specific studies of its effects in pregnant women, Tamoxifen should be avoided by women who are pregnant.
It is not known if Tamoxifen passes into breast milk. Nursing mothers should bottle-feed their babies.
Seniors may take Tamoxifen without special restriction.