Key facts about Tamoxifen
What dosages is Tamoxifen available in?
Tamoxifen is available as a 10 mg and 20 mg oral tablet.
What is Tamoxifen used for?
Tamoxifen is a selective estrogen receptor modulator (SERM) that is used for:
- Metastatic HR+ breast cancer
- Early stage HR+ breast cancer after surgery to reduce the risk of breast cancer coming back
- Ductal carcinoma in situ (DCIS) in women after breast surgery and radiation to reduce the risk of breast cancer coming back
- Lowering the risk of getting breast cancer in women who are considered high risk
How does Tamoxifen work?
Tamoxifen is a selective estrogen receptor modulator (SERM). Some breast cancers rely on hormones like estrogen to grow. These breast cancers are called hormone receptor-positive (HR+). Tamoxifen works to treat HR+ breast cancer by blocking estrogen from working on breast tissue. By blocking estrogen, cancer cells don’t have the fuel they need to grow, which stops breast cancer from growing and spreading.
How do I take Tamoxifen?
Tamoxifen is typically taken as 20 to 40 mg by mouth once daily. You will usually take Tamoxifen for 5 to 10 years depending on the condition being treated.
Is it safe for me to take Tamoxifen?
Tamoxifen is a safe and effective treatment when used for FDA licensed indications. However, like all medications, they may give you unwanted side effects. You should always discuss potential side effects with your physician to ensure the medication is suitable and right for you. You should not use this medication if you are pregnant or are taking a coumarin-type anticoagulant therapy or in women with a history of deep vein thrombosis or pulmonary embolus
Tamoxifen Common Side Effects
Common side effects of Tamoxifen:
- Hot flashes
- Vaginal discharge
- Swelling in the arms and legs
- Nausea
- Irregular or no monthly bleeding
- Vaginal bleeding
- Weight loss
- Skin changes
Tamoxifen Serious Side Effects
Serious side effects are rare with Tamoxifen. Contact your healthcare provider immediately if you experience any of the following.
- Blood clots in your veins or lungs: pain or swelling in your arms or legs, trouble breathing, chest pain, fast heartbeat
- Stroke: severe headache, sudden confusion, weakness on one side of your body, or trouble speaking or walking
- Cancers of the uterus: abnormal vaginal bleeding or discharge, pain or pressure in the area below the belly button (pelvis)
Effects of other drugs, drug classes and over-the-counter products on Tamoxifen
The following medications may interact with Tamoxifen:
- When Tamoxifen is used in combination with cytotoxic agents, there is increased risk of thromboembolic events occurring
- Coumadin and other coumarin type anticoagulant use with NOVALDEX is contraindicated.
- Rifampicin use may cause a reduction in Tamoxifen plasma levels
- Reduced efficacy on Tamoxifen has been reported with concomitant usage of some SSRI antidepressants (e.g. paroxetine)
- For the primary reduction of breast cancer risk, there is some evidence that hormone replacement therapy may reduce the effectiveness of NOVALDEX
Who makes Tamoxifen?
Various FDA-approved generic manufacturers
Is Tamoxifen safe in pregnancy?
Tamoxifen should not be used if you are pregnant. Based on data from animal studies, Tamoxifen might cause harm to your unborn baby. If you’re a woman who’s able to have babies, you should use non-hormonal birth control, like condoms or a diaphragm, while taking Tamoxifen and for 2 months after the last dose.
