What is Tamoxifen?
It is used in the treatment of breast cancer. Some tumours are dependent on female sex hormones, oestrogens, in order to grow. As an anti-oestrogen, Tamoxifen can prevent naturally occurring oestrogens attaching to tumour cells, which are dependent on them to grow.
How tamoxifen is taken
Tamoxifen is a tablet that should be swallowed whole with a glass of water. The tablets come in different strengths: 10mg, 20mg and 40mg. The drug is manufactured under several different brand names and these may appear on the tablets.
It’s also available as a sugar-free syrup for people who have difficulty swallowing tablets, but you may need to check whether this is available with your pharmacist.
Tamoxifen is usually prescribed as a single daily dose, and this should be taken at the same time each day. You may prefer to take the tablet with food, as it may make you feel sick and can leave a metallic taste in your mouth. It’s best to find a convenient time for you and stick to it.
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)
Before using tamoxifen
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 confined to a bed or chair
Some MEDICINES MAY INTERACT with tamoxifen. Tell your health care provider if you are taking any other medicines, especially any of the following:
• Anticoagulants (eg, warfarin) because the risk of bleeding may be increased
• Cytotoxic cancer medicines (eg, cisplatin) because the risk of developing blood clots may be increased
• Bupropion, cinacalcet, clobazam, duloxetine, fluoxetine, paroxetine, perphenazine, pimozide, quinidine, rifampin, sertraline, terbinafine, thioridazine, or ticlopidine because they may decrease tamoxifen’s effectiveness
• Fluorouracil or mitomycin C because they may increase the risk of tamoxifen’s side effects
• Aromatase inhibitors (eg, anastrozole, letrozole) because their effectiveness may be decreased by tamoxifen