tamoxifen citrate at a glance
Medicine class
Selective oestrogen receptor modulator, also described as an anti-oestrogen.
Main roles
Treatment of breast cancer and primary prevention in women assessed as having moderate or high risk.
Available forms
The selected products are tablets and an oral solution.
Important warning
Tamoxifen increases the risk of venous blood clots and requires review around surgery or prolonged immobility.
What is tamoxifen citrate used for?
The selected products cover the following licensed uses:
Treatment of breast cancer.
Primary prevention of breast cancer in appropriately assessed women at moderate or high risk.
Stimulation of ovulation in anovulatory infertility is licensed for the selected tablet product but not for the selected oral solution.
How does tamoxifen citrate work?
Tamoxifen competes with oestrogen for oestrogen receptors. In breast tissue, this reduces oestrogen-driven cell division, particularly in oestrogen receptor-positive disease. Its metabolites, including endoxifen, contribute to its activity.
tamoxifen citrate preparations and strengths
Oral solution
Route: Oral
Strengths: 10 mg/5 mL
Tablet
Route: Oral
Strengths: 10 mg, 20 mg
How to take tamoxifen citrate
Take tamoxifen by mouth exactly as prescribed. Swallow tablets with water. Keep the oral solution in its original container, protected from light. Do not refrigerate or freeze it.
Do not stop treatment without discussing it with the prescribing team.
The oral solution contains ethanol, sorbitol, glycerol and propylene glycol; ask a pharmacist if these ingredients may be a concern.
Do not drive or operate machinery if tamoxifen causes dizziness, visual disturbance or fatigue.
tamoxifen citrate side effects
Common or expected effects
- Hot flushes
- Nausea
- Fatigue
- Fluid retention
- Skin rash
- Vaginal discharge or bleeding
- Headache or light-headedness
- Vomiting, diarrhoea or constipation
- Leg cramps or muscle pain
- Changes in liver enzymes or fatty liver
Get urgent medical advice
- Symptoms of deep-vein thrombosis or pulmonary embolism, including a swollen painful limb, sudden breathlessness, chest pain or coughing blood
- Stroke symptoms, such as sudden weakness, speech difficulty or loss of coordination
- Severe blistering or peeling skin reactions
- Swelling of the face, tongue or throat, particularly with breathing or swallowing difficulty
- Palpitations, fainting or marked dizziness that could indicate a heart-rhythm problem
- Unexpected non-menstrual or postmenopausal bleeding, persistent discharge, pelvic pain or pressure, which requires prompt investigation
- New or worsening visual disturbance
tamoxifen citrate in pregnancy
Tamoxifen is contraindicated during pregnancy. Pregnancy should be excluded before treatment where relevant, and non-hormonal contraception is advised during treatment and for nine months after stopping. Anyone planning pregnancy or becoming pregnant while taking tamoxifen should contact their specialist promptly and should not stop treatment without advice.
tamoxifen citrate while breastfeeding
Breastfeeding is not recommended during tamoxifen treatment. Tamoxifen and active metabolites can enter and accumulate in human milk, and tamoxifen may suppress milk production. The oral solution is contraindicated during breastfeeding.
tamoxifen citrate interactions
Check all prescribed, non-prescription and herbal products with the treatment team. Important interactions include:
Paroxetine, fluoxetine, bupropion, quinidine or cinacalcet
Potent CYP2D6 inhibition can lower concentrations of active endoxifen and may reduce tamoxifen's effect; avoid the combination where possible.
Warfarin and other coumarin anticoagulants
Tamoxifen can markedly increase anticoagulant effects; careful coagulation monitoring is required, and the combination is contraindicated for primary prevention.
Anastrozole
Concurrent use is contraindicated in the selected products and has not improved adjuvant efficacy.
Common questions about tamoxifen citrate
Answers are fully visible for fast scanning and source review.
What is tamoxifen citrate used for?
It is mainly used to treat breast cancer and to reduce breast cancer risk in appropriately assessed women. The selected tablet is also licensed for anovulatory infertility.
How does tamoxifen citrate work against breast cancer?
It occupies oestrogen receptors in breast tissue, reducing the ability of oestrogen to stimulate receptor-positive cancer cells.
Sources
These sources were used to prepare and review this medicine page.
Prepared and reviewed by the iatroX editorial team.