Tamoxifen is a drug to treat breast cancer. This drug is also used to reduce the risk of developing breast cancer in women who are at high risk, for example because of a family history of breast cancer.

Tamoxifen works by blocking the effects of estrogen on the breasts. Some types of breast cancer require the hormone estrogen to develop. This way of working can be used in the treatment of breast cancer and prevention of breast cancer in women who are at high risk.

In addition, tamoxifen can also stimulate ovulation, so it can be used in the treatment of infertility in women.

Tamoxifen trademark:  Tamofen

What is Tamoxifen

class Prescription drug
Category Antiestrogen
Benefit Manage and reduce the risk of breast cancer
Consumed by Mature
Tamoxifen for pregnant and lactating women Category D:  There is positive evidence of risk to the human fetus, but the benefits may outweigh the risks, for example in dealing with a life-threatening situation.

It is not known whether tamoxifen is absorbed into breast milk or not. If you are breastfeeding, do not use this medication without telling your doctor.

Drug form Film-coated tablets

Precautions Before Taking Tamoxifen

Follow the doctor's recommendations and suggestions while undergoing treatment with tamoxifen. Before taking this drug, you need to pay attention to the following things:

  • Tell your doctor about any history of allergies you have. Tamoxifen should not be used by someone who is allergic to this drug.
  • Tell your doctor if you have or currently have liver disease , a blood clotting disorder, stroke , pulmonary embolism, deep vein thrombosis , high cholesterol, high triglycerides, diabetes , high blood pressure, or cataracts .
  • Tell your doctor if you need to be temporarily sedentary or immobilized, are  taking blood-thinning medication , or have a habit of smoking .
  • Tell your doctor if you are pregnant, breastfeeding or planning a pregnancy. Tamoxifen should not be used by women who are pregnant. Consult the type of effective contraception with your doctor to prevent pregnancy.
  • Tell your doctor that you are taking tamoxifen if you are having surgery, including dental surgery.
  • Consult your doctor if you or your family have a history of cancer, because tamoxifen can increase the risk of developing endometrial cancer, liver cancer, or uterine cancer.
  • Tell your doctor if you have menstrual problems or bleeding from the vagina outside of your menstrual cycle.
  • Tell your doctor if you are taking any medications, supplements or herbal products.
  • Immediately see a doctor if you have an allergic drug reaction, serious side effects, or an overdose after taking tamoxifen.

Dosage and Rules for Using Tamoxifen

The dose of tomoxifen prescribed by a doctor can be different for each patient. The following is the dosage of tamoxifen based on the purpose of treatment:

Purpose: To treat breast cancer

  • The dosage is 20–40 mg per day. Doses above 20 mg are usually divided into 2 times a day

Goal: Reduce the risk of breast cancer in high-risk women

  • The dose is 20 mg per day, for 5 years.

Purpose: Overcome infertility due to failure of ovulation in women with regular menstruation

  • Initial dose of 20 mg per day, given on days 2–5 of the menstrual cycle. Dosage can be increased to 40–80 mg per day in the next cycle.

Purpose: Overcome infertility due to failure of ovulation in women with irregular menstruation

  • Initial dose of 20 mg per day. If needed, the dose can be increased to 40-80 mg per day. If menstruation occurs, further treatment is carried out on the 2nd day of the menstrual cycle.

How to Take Tamoxifen Correctly

Follow the doctor 's recommendations and read the information listed on the drug packaging label before taking tamoxifen. Do not reduce or increase your dose without consulting your doctor first.

Tamoxifen can be taken before or after meals. Swallow the tablet whole with the help of a glass of water. Do not crush or chew the tablets.

Use tamoxifen regularly for maximum treatment. Do not stop using the drug without consulting your doctor first.

If you forget to take tamoxifen, it is advisable to drink it immediately if the break with the next consumption schedule is not too close. If it's close, ignore it and don't double the dose.

Store tamoxifen at room temperature and avoid exposure to direct sunlight. Keep this drug out of reach of children.

Tamoxifen Interactions with Other Drugs

The following are the effects of drug interactions that can occur if tamoxifen is used with other drugs:

  • Increased risk of bleeding when used with blood thinners, such as  warfarin
  • Increased risk of developing blood clots when used with other anticancer drugs, such as doxorubicin, daunorubicin, or vincristine
  • Increased tamoxifen blood levels when used with bromocriptine
  • Decreased blood levels of tamoxifen when used with CYP3A4 inducers, such as rifampicin , or aminoglutethimide
  • Decreased therapeutic effect of tamofixen when used w/ CYP2D6 inhibitors, such as paroxetine, fluoxetine , cinacalcet, bupropion , or quinidine
  • Decreased effectiveness of tamoxifen when used with birth control pills or hormone replacement therapy drugs
  • Decreased letrozole levels in the blood

Side Effects and Dangers of Tamoxifen

Some of the side effects that can arise after using tamoxifen are:

  • Nausea or stomach cramps
  • Headache or dizziness
  • Thin hair
  • Loss of sexual desire, especially in men
  • Excessive fatigue
  • Weight loss
  • Warmth in the face, neck, or chest ( flushing )
  • Depression
  • Disturbance of the menstrual cycle or vaginal discharge

Consult a doctor if the side effects above do not subside immediately or get worse. Immediately see a doctor if you experience an allergic drug reaction or more serious side effects, such as:

  • Visual disturbances, such as blurred vision, tunnel vision, or eye pain
  • The appearance of a new lump in the breast
  • The appearance of bleeding outside the menstrual cycle or disruption of the menstrual cycle
  • Liver disease which can be characterized by symptoms, such as jaundice, stomach pain, excessive fatigue, or loss of appetite
  • High levels of calcium in the blood which can be characterized by symptoms, such as constipation, muscle weakness, bone pain, feeling tired, confused, or weak

In addition, the use of tamoxifen can also increase the risk of developing blood clots which can block blood vessels and cause strokes or pulmonary embolism.

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