Toremifene (Fareston®)

OncoLink Team
Last Modified: January 7, 2016

Pronounced: tore-EM-i-feen

Classification: Antiestrogen

About Toremifene

Toremifene is in a class of medications called selective estrogen receptor modulators or SERMs. Most breast cancers need supplies of estrogen (a female hormone produced by the body) to grow. Toremifene decreases the risk of developing invasive breast cancer by blocking the effects of estrogen on breast tissue. This may stop the development of tumors that need estrogen to grow.

How to Take Toremifene

Toremifene comes as a tablet to be taken orally (by mouth) around the same time each day, with or without food.

The blood levels of this medication can be affected by certain foods and medications, so they should be avoided. These include: grapefruit, grapefruit juice, verapamil, ketoconazole, rifampin, phenytoin, St. John’s wort, and modafanil, among others. Be sure to tell your healthcare provider about all medications and supplements you take.

Storage and Handling     

Store this medication at room temperature in the original container. If you prefer to use a pillbox, discuss this with your oncology pharmacist. Ask your oncology team where to return any unused medication for disposal. Do not flush down the toilet or throw in the trash.

Where do I get this medication?

Toremifene is available through select pharmacies. Your oncology team will work with your prescription drug plan to identify an in-network specialty pharmacy for distribution of this medication and shipment directly to your home. 

Insurance Information

This medication may be covered under your prescription drug plan. Patient assistance may be available to qualifying individuals without prescription drug coverage. Co-pay cards, which reduce the patient co-pay responsibility for eligible commercially (non-government sponsored) insured patients, are also available. Your care team can help you find these resources, if they are available.

Possible Side Effects of Toremifene

There are a number of things you can do to manage the side effects of toremifene. Talk to your doctor or nurse about these recommendations. They can help you decide what will work best for you. These are some of the most common side effects:

Hot Flashes

There are a few things you can do to help with hot flashes. Several medications have been shown to help with symptoms, including clonidine (a blood pressure medication), low doses of certain antidepressants (such as venlafaxine and Prozac), and gabapentin. Non-medical recommendations include:

  • Keep well-hydrated with eight glasses of water daily.
  • Drink ice water or apply an ice pack at the onset of a hot flash.
  • Wear cotton or lightweight, breathable fabrics and dress in layers so you can adjust as needed.
  • Exercise on a regular basis.
  • Try practicing meditation or relaxation exercises to manage stress, which can be a trigger.
  • Avoid triggers such as warm rooms, spicy foods, caffeinated beverages, and alcohol.

Nausea and/or Vomiting

Talk to your doctor or nurse so they can prescribe medications to help you manage nausea and vomiting. In addition, dietary changes may help. Avoid things that may worsen the symptoms, such as heavy or greasy/fatty, spicy or acidic foods (lemons, tomatoes, oranges). Try antacids, (e.g. milk of magnesia, calcium tablets such as Tums), saltines, or ginger ale to lessen symptoms.

Call your doctor or nurse if you are unable to keep fluids down for more than 12 hours or if you feel lightheaded or dizzy at any time.

Blood Clots

This medication increases the risk of developing a blood clot, which most frequently occurs in the calves, and can travel from there to the lungs. Women at higher risk for developing blood clots include those with a family history of blood clots, heavy smokers, those who have an inactive lifestyle, older women, and those with other predisposing medical problems. Women with any one of these risk factors may want to consider another therapy that does not have this side effect.

Signs of a blood clot in the leg may include any of the following: leg pain, warmth, swelling of one leg more than the other. Signs of a blood clot in the lung could include: fever, shortness of breath that comes on very quickly, racing heart, chest pain (that tends to be worse when you take a deep breath). If you have any of these signs or symptoms of blood clots, you will need to be seen immediately so that you can be treated. Blood thinners can be given. Call your doctor or nurse.

Heart Problems

This medication can cause slow or abnormal heartbeats or an abnormal heart rhythm called QT prolongation. Notify your healthcare provider right away if you feel abnormal heartbeats or if you feel dizzy or faint.

Depression

Depression may occur as a result of some of the biological changes occurring in your body and/or your emotional response to some of these changes. Symptoms of depression may include sadness, sleep and appetite changes, as well as a lack of desire to do the activities you once enjoyed. This is very treatable. Please talk to your doctor or nurse if you feel that you are experiencing any of these symptoms.

Bone Metastases

Patients with cancer that has spread to the bone may experience pain or discomfort at the tumor site after starting toremifene, but this should decrease over time and should be managed with pain medication.

In addition, patients with bone metastases may develop hypercalcemia (high levels of calcium in the blood) and may require hospitalization to correct this. Symptoms of hypercalcemia include increased thirst and urination, nausea, constipation, muscle weakness, confusion or changes in mental status. Report any symptoms to your care provider.

Fatigue

Fatigue is very common during cancer treatment and is an overwhelming feeling of exhaustion that is not usually relieved by rest. While on cancer treatment, and for a period after, you may need to adjust your schedule to manage fatigue. Plan times to rest during the day and conserve energy for more important activities. Exercise can help combat fatigue; a simple daily walk with a friend can help.  Talk to your healthcare team for helpful tips on dealing with this side effect.

Vaginal Dryness

Vaginal dryness and related painful intercourse is one of the more common side effects of cancer therapy in women. Vaginal lubricants and moisturizers (longer lasting form of moisturizers) can help with these concerns. Talk to your healthcare team for more suggestions in managing this side effect.

Vaginal Bleeding

There is a very small of developing endometrial cancer while taking this medication. Healthcare professionals believe that the benefits of this medication outweigh this risk. Women should promptly report any menstrual irregularities, vaginal bleeding, pelvic pressure/pain, or any vaginal discharge, as these may be symptoms of endometrial cancer. An endometrial biopsy should be done if any of these symptoms occur.

Cataracts

Women taking this medication have an increased risk of getting cataracts. You should have a yearly eye exam by an ophthalmologist. Report any vision changes, cloudy or blurry vision, difficulty with night vision, sensitivity to light, fading or yellowing of colors, as these can be symptoms of cataracts.

Other Reported Side Effects

Other side effects reported include: headache, swelling of the hands and/or feet, dizziness, weight gain, vaginal discharge and insomnia. Mood changes or depression can occur. Please talk to your healthcare provider if you feel that you are troubled by these symptoms.

Sexual & Reproductive Concerns

Women may experience menopausal effects including hot flashes and vaginal dryness. In addition, the desire for sex may decrease during treatment.

Exposure of an unborn child to this medication could cause birth defects, so you should not become pregnant while on this medication. Effective birth control is necessary during treatment even if your menstrual cycle stops. You should consult with your healthcare team before breastfeeding while receiving this medication.

 

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From the National Cancer Institute