Tamodex-20

Indications

Tamoxifen is a hormone-blocking medicine used mainly for breast cancer. It is used to treat hormone receptor-positive breast cancer (cancer that grows in response to oestrogen) in women and men, to lower the chance of the cancer coming back after surgery, to treat advanced breast cancer, and to reduce the risk of breast cancer in some women at high risk. Specialists sometimes use it for other conditions, such as to help ovulation in certain fertility problems.

How It Works

Tamoxifen is a selective oestrogen receptor modulator (SERM). In breast tissue it attaches to oestrogen receptors and blocks oestrogen from reaching them, which slows or stops the growth of oestrogen-sensitive cancer cells. In other tissues, such as the womb lining and bone, it can act a little like oestrogen, which explains some of its benefits and risks.

Dosage and Administration

Take exactly as prescribed by your cancer specialist. It is usually taken once a day, at about the same time, with or without food, and swallowed with water. Treatment for early breast cancer commonly lasts 5 to 10 years. Doses for other uses, such as fertility, are set by the specialist. If you miss a dose, take it when you remember unless it is nearly time for the next one; do not double up. Do not stop without talking to your doctor.

Interactions

• Some antidepressants and other medicines that block the liver enzyme CYP2D6, such as Fluoxetine, Paroxetine, Bupropion and Quinidine, may make Tamoxifen less effective; your doctor may choose alternatives.
• Warfarin and similar blood thinners: Tamoxifen increases their effect and bleeding risk; close monitoring is needed.
• Aromatase inhibitors (such as Letrozole or Anastrozole) are not taken at the same time as Tamoxifen.
• Oestrogen-containing medicines (contraceptive pills, hormone replacement therapy) may reduce its effect.
• Rifampicin can lower Tamoxifen levels.

Contraindications

• Allergy to Tamoxifen.
• Pregnancy.
• For risk reduction only: a history of blood clots in the legs or lungs, or current use of Warfarin.
• Children, unless prescribed by a specialist.

Side Effects

Common side effects include hot flushes, sweating, vaginal discharge or dryness, irregular or stopped periods, nausea, tiredness, fluid retention, leg cramps, joint pain, headache, hair thinning and skin rash. Tumour flare (temporary increase in bone pain) can occur at the start in advanced cancer.

Less common but serious effects include blood clots in the legs or lungs, stroke, cancer or polyps of the womb lining, cataracts and other eye changes, liver problems and raised calcium in the blood.

Get urgent medical help if you have a painful swollen leg, sudden chest pain or breathlessness, sudden weakness, numbness or trouble speaking, vaginal bleeding after menopause or unusual bleeding or pelvic pain, yellowing of the skin or eyes, or sudden changes in vision.

Pregnancy and Lactation

Tamoxifen can harm an unborn baby and must not be used in pregnancy. Women who could become pregnant should use non-hormonal contraception (such as a condom or copper coil) during treatment and for at least 2 months after stopping, or longer if advised. It can increase fertility in women who still have periods, so contraception is important. Do not breastfeed while taking Tamoxifen.

Precautions and Warnings

Tell your doctor about any history of blood clots, stroke, liver disease, cataracts, abnormal vaginal bleeding, or if you are due to have surgery or will be immobile for a long time (Tamoxifen may be paused). Have regular gynaecological check-ups and report any abnormal vaginal bleeding. Eye checks may be advised. Avoid smoking, which raises clot risk.

Overdose

Overdose may cause tremor, unsteadiness, dizziness and heart rhythm changes. Contact a doctor or poison centre straight away; treatment is supportive.

Therapeutic Class

Antineoplastic hormone therapy; selective oestrogen receptor modulator (SERM), anti-oestrogen.

Storage

Store below 30°C in a dry place, away from light and out of the reach of children.