Generic Name: toremifene (Oral route)
Toremifene prolongs the QTc interval in a dose- and concentration-related manner and may cause a type of ventricular tachycardia called Torsade de pointes. This could result in syncope, seizures, and/or death. Toremifene should not be prescribed to patients with congenital/acquired QT prolongation, uncorrected hypokalemia, or uncorrected hypomagnesemia. Drugs known to prolong the QT interval and strong CYP3A4 inhibitors should be avoided .
Commonly used brand name(s)
In the U.S.
Available Dosage Forms:
Therapeutic Class: Antiestrogen
Uses For Fareston
Toremifene is used to treat metastatic breast cancer (cancer that has spread) that is hormone-receptor positive in women who have already stopped menstruating (postmenopausal).
Many of the breast cancer tumors will grow when estrogen is available in the body. This medicine blocks the effects of the estrogen hormone in the body. As a result, the amount of estrogen that the tumor is exposed to is reduced, which will limit the growth of the tumor.
Before you begin treatment with toremifene, you and your doctor should talk about the good this medicine will do as well as the risks of using it.
This medicine is available only with your doctor's prescription.
Before Using Fareston
In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For this medicine, the following should be considered:
Tell your doctor if you have ever had any unusual or allergic reaction to this medicine or any other medicines. Also tell your health care professional if you have any other types of allergies, such as to foods, dyes, preservatives, or animals. For non-prescription products, read the label or package ingredients carefully.
Toremifene is not indicated for use in the pediatric population. Safety and efficacy have not been established.
Appropriate studies performed to date have not demonstrated geriatric-specific problems that would limit the usefulness of toremifene in the elderly. However, elderly patients are more likely to have age-related liver problems, which may require an adjustment in the dose for patients receiving toremifene.
|All Trimesters||D||Studies in pregnant women have demonstrated a risk to the fetus. However, the benefits of therapy in a life threatening situation or a serious disease, may outweigh the potential risk.|
There are no adequate studies in women for determining infant risk when using this medication during breastfeeding. Weigh the potential benefits against the potential risks before taking this medication while breastfeeding.
Interactions with Medicines
Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking this medicine, it is especially important that your healthcare professional know if you are taking any of the medicines listed below. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.
Using this medicine with any of the following medicines is not recommended. Your doctor may decide not to treat you with this medication or change some of the other medicines you take.
Using this medicine with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.
- Arsenic Trioxide
- Sodium Phosphate
Interactions with Food/Tobacco/Alcohol
Certain medicines should not be used at or around the time of eating food or eating certain types of food since interactions may occur. Using alcohol or tobacco with certain medicines may also cause interactions to occur. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.
Using this medicine with any of the following is usually not recommended, but may be unavoidable in some cases. If used together, your doctor may change the dose or how often you use this medicine, or give you special instructions about the use of food, alcohol, or tobacco.
- Grapefruit Juice
Other Medical Problems
The presence of other medical problems may affect the use of this medicine. Make sure you tell your doctor if you have any other medical problems, especially:
- Blood clots, or history of—Use is usually not recommended in patients with this condition.
- Bone problems or
- Congestive heart failure or
- Heart rhythm problems (e.g., QT prolongation) or
- Leukopenia (low white blood cells in the blood) or
- Thrombocytopenia (low platelets in the blood)—Use with caution. May make these conditions worse.
- Heart rhythm problems (e.g., congenital or acquired long QT syndrome) or
- Hypokalemia (low potassium in the blood), uncorrected or
- Hypomagnesemia (low magnesium in the blood), uncorrected—Should not be used in patients with these conditions.
- Liver disease (e.g., cirrhosis or fibrosis)—Use with caution. The effects may be increased because of slower removal of the medicine from the body.
- Unusual growth of the lining of the uterus (womb)—Long-term use of toremifene is usually not recommended.
Proper Use of Fareston
Take this medicine only as directed by your doctor. Do not take more of it, do not take it more often, and do not take it for a longer time than your doctor ordered.
Toremifene sometimes causes mild nausea and vomiting. However, it may have to be taken for several weeks or months to be effective. Even if you begin to feel ill, do not stop using this medicine without first checking with your doctor. Ask your doctor for ways to lessen these effects.
You may take this medicine with or without food.
The dose of this medicine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.
The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.
- For oral dosage form (tablets):
- For breast cancer:
- Adults—60 milligrams (mg) once a day.
- Children—Use is not recommended.
- For breast cancer:
If you miss a dose of this medicine, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not double doses.
Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light. Keep from freezing.
Keep out of the reach of children.
Do not keep outdated medicine or medicine no longer needed.
Ask your healthcare professional how you should dispose of any medicine you do not use.
Precautions While Using Fareston
It is very important that your doctor check your progress at regular visits to make sure that this medicine is working properly. Blood tests may be needed to check for unwanted effects. It is important for women to have regular gynecologic check-ups while taking this medicine.
It is unlikely that a postmenopausal woman may become pregnant. But, you should know that using this medicine while you are pregnant could harm your unborn baby. Use an effective form of birth control to keep from getting pregnant. If you think you have become pregnant while using the medicine, tell your doctor right away.
This medicine can cause changes in heart rhythms, such as a condition called QT prolongation. It may change the way your heart beats and cause fainting or serious side effects in some patients. Contact your doctor right away if you have any symptoms of heart rhythm problems, such as fast, pounding, or uneven heartbeats.
Hypercalcemia (high calcium in the blood) and tumor flare (increased size of a tumor) are more likely to occur in patients with bone problems who are taking this medicine. Stop using this medicine and check with your doctor right away if you have abdominal or stomach pain, confusion, constipation, depression, dry mouth, increased urination, loss of appetite, metallic taste, muscle weakness, pain and swelling in the bones and muscles surrounding a tumor, thirst, unusual tiredness, or weight loss.
Toremifene can temporarily lower the number of white blood cells in your blood, increasing the chance of getting an infection. It can also lower the number of platelets, which are necessary for proper blood clotting. If this occurs, there are certain precautions you can take, especially when your blood count is low, to reduce the risk of infection or bleeding:
- If you can, avoid people with infections. Check with your doctor immediately if you think you are getting an infection or if you get a fever or chills, cough or hoarseness, lower back or side pain, or painful or difficult urination.
- Check with your doctor immediately if you notice any unusual bleeding or bruising; black, tarry stools; blood in the urine or stools; or pinpoint red spots on your skin.
- Be careful when using a regular toothbrush, dental floss, or toothpick. Your medical doctor, dentist, or nurse may recommend other ways to clean your teeth and gums. Check with your medical doctor before having any dental work done.
- Do not touch your eyes or the inside of your nose unless you have just washed your hands and have not touched anything else in the meantime.
- Be careful not to cut yourself when you are using sharp objects such as a safety razor or fingernail or toenail cutters.
- Avoid contact sports or other situations where bruising or injury could occur.
This medicine may cause you to have bleeding from the vagina, especially when you first start using it. If the bleeding continues or is bothersome, check with your doctor right away.
Grapefruits and grapefruit juice may increase the effects of toremifene by increasing the amount of this medicine in your body. You should not eat grapefruit or drink grapefruit juice while you taking this medicine.
Do not take other medicines unless they have been discussed with your doctor. This includes prescription or nonprescription (over-the-counter [OTC]) medicines and herbal (e.g., St. John's wort) or vitamin supplements.
Fareston Side Effects
Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.
Also, because of the way this medicine acts on the body, there is a chance that it might cause other unwanted effects that may not occur until months or years after the medicine is used. Some patients who have used toremifene have developed cancer of the uterus (womb), although it is not known for sure if it was caused by the medicine. Discuss this possible effect with your doctor.
Check with your doctor immediately if any of the following side effects occur:Less common
- Abdominal or stomach pain
- arm, back, or jaw pain
- blurred vision
- change in vaginal discharge
- changes in skin color
- changes in vision
- chest pain or discomfort
- chest tightness or heaviness
- decreased urine output
- dilated neck veins
- dizziness or lightheadedness
- dry mouth
- extreme fatigue
- fast, slow, or irregular heartbeat
- inability to speak incoherent speech
- increased urination
- irregular breathing
- irregular heartbeat
- loss of appetite
- metallic taste
- muscle weakness
- pain or discomfort in the arms, jaw, back, or neck
- pain or feeling of pressure in the pelvis
- pain, tenderness, or swelling of the foot or leg
- severe or sudden headache
- shortness of breath
- slurred speech
- sudden shortness of breath or troubled breathing
- swelling of the face, fingers, feet, or lower legs
- temporary blindness
- tenderness, pain, swelling, warmth, skin discoloration, and prominent superficial veins over the affected area
- tightness in the chest
- troubled breathing
- unusual tiredness
- vaginal bleeding
- weakness in the arm and/or leg on one side of the body, sudden and severe
- weight gain
- weight loss
- Chest pain
- Black, tarry stools
- bleeding gums
- blood in the urine or stools
- clay-colored stools
- dark urine
- painful or difficult urination
- pinpoint red spots on the skin
- sore throat
- sores, ulcers, or white spots on the lips or in the mouth
- swollen glands
- unpleasant breath odor
- unusual bleeding or bruising
- unusual tiredness or weakness
- vomiting of blood
- yellow eyes or skin
Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:More common
- decreased vision
- dry eyes
- feeling of warmth
- redness of the face, neck, arms, and occasionally, upper chest
- sudden sweating
- white or brownish vaginal discharge
- Bone pain
- changes in vision
- double vision
- eye pain
- Blistering, crusting, irritation, itching, or reddening of the skin
- cracked, dry, or scaly skin
- difficulty having a bowel movement (stool)
- dizziness or lightheadedness
- feeling of constant movement of self or surroundings
- feeling unusually cold
- hair loss
- itching skin
- lack or loss of strength
- partial or slight paralysis
- sensation of spinning
- shakiness in the legs, arms, hands, or feet
- thinning of the hair
- trembling or shaking of the hands or feet
Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.
Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.
See also: Side effects (in more detail)
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