Fareston (Toremifene)

Fareston (toremifene) is a medication used to treat metastatic breast cancer in postmenopausal women. It works by blocking the effects of estrogen on breast tissue, which can help slow or stop the growth of cancers that rely on estrogen. Toremifene is part of a class of drugs called selective estrogen receptor modulators (SERMs). Each tablet contains a form of toremifene that provides 60 mg of the active drug.

Directions

Fareston is taken by mouth as a tablet once daily. The standard dosage is 60 mg per day, with or without food. Don’t stop taking Fareston or adjust the dose without consulting a healthcare provider. If a dose is missed, patients should take it as soon as they remember unless it's almost time for the next scheduled dose. In that case, they should skip the missed dose and continue their regular schedule rather than taking two doses.

Ingredients

The active ingredient in Fareston is toremifene citrate.

Cautions

• Before using this medication, you may want to consult a healthcare provider about the following:
  • Any existing health conditions
  • Any allergies
  • A list of all medications currently being taken
• Fareston can affect the heart's electrical rhythm and may cause a dangerous heart rhythm problem that can lead to fainting, seizures, or death, especially in people with existing heart conditions or electrolyte imbalances.
• This medication should not be used by people with known long QT syndrome, and doctors may order heart tests and blood work to monitor heart rhythm and electrolyte levels during treatment.
• Fareston may cause liver problems, including liver inflammation, elevated liver enzymes, or jaundice, so liver function tests are usually checked regularly.
• Some people with breast cancer that has spread to the bones may experience a temporary worsening of bone pain or tumor swelling when starting treatment, which does not mean the medication is failing.
• Fareston may raise calcium levels in the blood, especially early in treatment, and severe cases may require stopping the medication.
• Long-term use may increase the risk of uterine conditions such as thickening of the uterine lining, polyps, or uterine cancer, so regular gynecologic exams are recommended.
• People with a history of blood clots are generally advised not to use Fareston because it may increase the risk of thromboembolic events.
• Rare changes in white blood cell or platelet counts have been reported, and blood tests may be used to monitor for these effects.
• Fareston can harm an unborn baby and should not be used during pregnancy, and anyone who becomes pregnant while taking it should contact their healthcare provider immediately.
• Although Fareston is intended for postmenopausal women, those who could become pregnant should use effective non-hormonal birth control while taking this medication.

Contraindications

Avoid taking or using this medication if any of the following apply:

• Known hypersensitivity to toremifene or any ingredients of the medication
• QT prolongation or history of QT prolongation on electrocardiogram
• Uncorrected hypokalemia (low potassium levels in the blood)
• Uncorrected hypomagnesemia (low magnesium levels in the blood)
• Congenital long QT syndrome or family history of the condition
• Combined use with medications known to prolong the QT interval

Side Effects

Common side effects of Fareston include:

• Hot flashes
• Sweating
• Nausea
• Vaginal discharge
• Dizziness
• Fluid retention (edema)

These side effects are related to Fareston's anti-estrogen effects and often appear early in treatment. More serious side effects are less common but may include blood clots, heart problems (such as heart attack or abnormal heart rhythm), eye-related effects like cataracts or visual changes, and uterine effects such as abnormal vaginal bleeding. Contact a healthcare provider immediately if you develop chest pain, shortness of breath, leg swelling, vision changes, yellowing of the skin or eyes, or unusual vaginal bleeding.