TAMOXIFEN (Systemic)

Some commonly used brand names are:

In the U.S.?

• Nolvadex

In Canada?

• Apo-Tamox
• Gen-Tamoxifen
• Nolvadex
• Nolvadex-D
• Novo-Tamoxifen
• PMS-Tamoxifen
• Tamofen
• Tamone

Generic name product may be available in the U.S.

Category

• Antineoplastic

Description

Tamoxifen (ta-MOX-i-fen) is a medicine that blocks the effects of theestrogen hormone in the body. It is used to treat breast cancer in women ormen. It may also be used to treat other kinds of cancer, as determined byyour doctor.

Tamoxifen also may be used to reduce the risk of developing breast cancerin women who have a high risk of developing breast cancer. Women at high riskfor developing breast cancer are at least 35 years of age and have a combinationof risk factors that make their chance of developing breast cancer 1.67% ormore over the next 5 years. Your doctor will help to determine your risk ofdeveloping breast cancer.

The following are risk factors that may increase your chance of developingbreast cancer:
• If you have close family members (mother, sister, or daughter) withbreast cancer
• If you have ever had a breast biopsy or if high-risk changes in yourbreast(s) have been found from a breast biopsy
• If you have never been pregnant or if your first pregnancy occurredat a late age
• If your first menstrual period occurred at an early age

The exact way that tamoxifen works against cancer is not known, but itmay be related to the way it blocks the effects of estrogen on the body.

Before you begin treatment with tamoxifen, you and your doctor should talkabout the good this medicine will do as well as the risks of using it.

Tamoxifen is available only with your doctor's prescription, in the followingdosage form:

Oral
• Tablets (U.S. and Canada)

Before Using This Medicine

In deciding to use a medicine,the risks of taking the medicine must be weighed against the good it willdo. This is a decision you and your doctor will make. For tamoxifen, the followingshould be considered:

Allergies?Tell your doctor if you have ever had any unusual orallergic reaction to tamoxifen.

Pregnancy?Tell your doctor if you are pregnant or if you intendto become pregnant. Tamoxifen should not be used to reduce the risk of breastcancer if you are pregnant of if you intend to become pregnant. Tamoxifenuse in women has been shown to cause miscarriages, birth defects, death ofthe fetus, and vaginal bleeding. Studies in rats and rabbits have shown thattamoxifen causes miscarriages, death of the fetus, and slowed learning. Studiesin animals also have shown that tamoxifen may cause some of the same problemsas those caused by an estrogen called diethylstilbestrol (DES). DES causesgenital tract problems and, rarely, an increased risk of cancer of the cervixor vagina in daughters of women who took it during their pregnancy. It isnot known whether tamoxifen causes these same problems.

Be sure that you have discussed this with your doctor before taking thismedicine. It is best to use some kind of birth control while you are takingtamoxifen and for about 2 months after you stop taking it. However, do notuse oral contraceptives (?the Pill?) since they may interferewith this medicine. Tell your doctor right away if you think you have becomepregnant while taking tamoxifen.

Breast-feeding?Because this medicine may cause serious side effects,breast-feeding is generally not recommended while you are taking it.

Older adults?Many medicines have not been studied specificallyin older people. Therefore, it may not be known whether they work exactlythe same way they do in younger adults. Although there is no specific informationcomparing use of tamoxifen in the elderly with use in other age groups, thismedicine is not expected to cause different side effects or problems in olderpeople than it does in younger adults.

Other medicines?Although certain medicines should not be usedtogether at all, in other cases two different medicines may be used togethereven if an interaction might occur. In these cases, your doctor may want tochange the dose, or other precautions may be necessary. Tell your health careprofessional if you are taking any other prescription or nonprescription (over-the-counter[OTC]) medicine. If you are taking tamoxifen to reduce the risk of breastcancer, it is especially important that your health care professional knowif you are taking the following:

• Anticoagulant, coumarin-type (blood thinners)?Blood thinners(e.g., warfarin [Coumadin]) should not be used with tamoxifen when used toreduce the risk of developing breast cancer in women who have a high riskof developing breast cancer. If you need to take blood thinners, your bloodclotting times should be monitored by your doctor.

• Cytotoxic medicines?These are medicines that damage cells.If you take these medicines with tamoxifen, you may have an increased riskof blood clots.

Other medical problems?The presence of other medicalproblems may affect the use of tamoxifen. Make sure you tell your doctor ifyou have any other medical problems, especially:

For all patients
• Blood problems or
• Cataracts or other eye problems?Tamoxifen may also cause theseproblems

• High cholesterol levels in the blood?Tamoxifen can increasecholesterol levels

When used for reducing the risk for developing breast cancer in high-riskwomen or in women with Ductal Carcinoma in Situ (DCIS)
• Blood clots (or history of) or
• Pulmonary embolism (or history of) or
• Stroke or
• Uterine (womb) cancer?May increase risk of serious side effectsfrom tamoxifen.

Proper Use of This Medicine

Use this medicine only as directed by your doctor. Do not use moreor less of it, and do not use it more often than your doctor ordered. Theexact amount of medicine you need has been carefully worked out. Taking toomuch may increase the chance of side effects, while taking too little maynot improve your condition.

Tamoxifen sometimes causes mild nausea and vomiting. However, it may haveto be taken for several weeks or months to be effective. Even if you beginto feel ill, do not stop using this medicine withoutfirst checking with your doctor. Ask your health care professionalfor ways to lessen these effects.

Swallow the tablets whole with a drink of water. You can take the tabletswith or without food.

If you vomit shortly after taking a dose of tamoxifen, check with yourdoctor. You will be told whether to take the dose again or to wait until thenext scheduled dose.

Dosing?The dose of tamoxifen will be different fordifferent patients. Follow your doctor's orders or thedirections on the label. The following information includes only theaverage doses of tamoxifen. If your dose is different,do not change it unless your doctor tells you to do so.

• For oral dosage form (tablets)
  • For breast cancer in women or men:
    • Adults?20 to 40 milligrams (mg) daily.
  • For reducing the risk of developing breast cancer in high-risk women:
    • Adults?20 milligrams (mg) a day, for five years
  • For reducing the risk of developing invasive breast cancer in womenwith ductal carcinoma in situ:
    • Adults?20 milligrams (mg) a day, for five years

Missed dose?If you miss a dose of this medicine, do not takethe missed dose at all and do not double the next one. Instead, go back toyour regular dosing schedule and check with your doctor.

Storage?To store this medicine:

• Keep out of the reach of children.
• Store away from heat and direct light.
• Do not store in the bathroom, near the kitchen sink, or in otherdamp places. Heat or moisture may cause the medicine to break down.
• Do not keep outdated medicine or medicine no longer needed. Be surethat any discarded medicine is out of the reach of children.

Precautions While Using This Medicine

It is very important that your doctor check your progress atregular visits to make sure that this medicine is working properlyand to check for unwanted effects.

A woman should contact her healthcare profession right away if she develops:

• Changes in vaginal discharge or
• Changes in vision or
• Coughing up blood or
• Leg swelling or tenderness or
• Menstrual irregularities or
• New breast lumps or
• Pelvic pain or pressure or
• Sudden chest pain or
• Unexplained shortness of breath or
• Vaginal bleeding

If you seek medical attention for any reason, be sure to tell your healthcareprofessional that you take tamoxifen or have taken tamoxifen.

For women: Tamoxifen may make you more fertile. It is best to use sometype of birth control while you are taking it. However, do not use oral contraceptives(?the Pill?) since they may change the effects of tamoxifen. Tellyour doctor right away if you think you have become pregnant while takingthis medicine.

Side Effects of This Medicine

Along with its needed effects,a medicine may cause some unwanted effects. Some side effects will have signsor symptoms that you can see or feel. Your doctor will watch for others bydoing certain tests.

Also, because of the way this medicine acts on the body, there is a chancethat it might cause other unwanted effects that may not occur until monthsor years after the medicine is used. Tamoxifen increases the chance of cancerof the uterus (womb) in some women taking it. Tamoxifen may cause blockagesto form in a vein, lung, or brain. In women, tamoxifen may cause cancer orother problems of the uterus (womb). It also causes liver cancer in rats.In addition, tamoxifen has been reported to cause cataracts and other eyeproblems. Discuss these possible effects with your doctor.

Check with your doctor as soon as possibleif any of the following side effects occur:

For both females and males

Less common or rare

Anxiety; blistering, peeling, or looseningof skin and mucous membranes; blurred vision; chest pain; confusion; cough; dizziness; fainting; fast heartbeat; lightheadedness; pain or swelling in legs; shortness of breath or trouble breathing; weakness or sleepiness; yellow eyes or skin

For females only

Less common or rare

Change in vaginal discharge; chills; fever; hoarseness; lower back or side pain; pain or feelingof pressure in pelvis; pain, redness, or swellingin your arm or leg; painful or difficult urination; rapid shallow breathing; skin rash or itching over the entire body; sweating; vaginal bleeding; wheezing

For females and males

Frequency not determined

Bloating; constipation; darkened urine; diarrhea; difficult breathing; indigestion; itching; joint or muscle pain; large, hard skin blisters; large hive-likeswelling on face, eyelids, lips, tongue, throat, hands, legs, feet, and sexorgans; loss of appetite; nausea; pain in stomach or side, possibly radiatingto the back; red, irritated eyes; red skin lesions, often with a purple center; sorethroat; sores, ulcers or white spots in mouth oron lips; unusual tiredness or weakness; vomiting

This medicine may also cause the followingside effect that your doctor will watch for:

For both females and males

Less common or rare

Cataracts in the eyes or other eye problems; liver problems

Other side effects may occur that usually donot need medical attention. These side effects may go away during treatmentas your body adjusts to the medicine. Also, your health care professionalmay be able to tell you about ways to prevent or reduce some of these sideeffects. Check with your health care professional if any of the followingside effects continue or are bothersome or if you have any questions aboutthem:

For both females and males

Less common

Bone pain; headache; nausea and/or vomiting (mild); skin rash or dryness

For females only

More common

Absent, missed, or irregular periods; confusion; decrease in amount of urine; feeling of warmth redness of the face, neck, arms and occasionally,upper chest; lower back or side pain; menstrual changes; nausea; noisy, rattling breathing; painful ordifficult urination; rapid, shallow breathing; skin changes; stopping of menstrualbleeding; swelling of fingers, hands, feet, or lowerlegs; troubled breathing at rest; vaginal bleeding; weight gain; weight loss; white or brownish vaginal discharge

Less common or rare

Abdominal cramps; black, tarry stools; bleeding gums; blood inurine or stools; Bluish color changes in skin color; discouragement; feelingsad or empty; irritability; itching in genital area; lack of appetite; loss of interest or pleasure; pain; pinpoint red spots on skin; stomachor pelvic discomfort, aching or heaviness; swelling; trouble concentrating; trouble sleeping; unusual bleeding or bruising

For males only

Less common

decreased interest in sexual intercourse; inability to have or keep an erection; loss in sexualability, desire, drive, or performance

This medicine may infrequently cause hair thinning orpartial loss of hair.

Other side effects not listed above may also occur in some patients. Ifyou notice any other effects, check with your doctor.

Additional Information

Once a medicine has been approvedfor marketing for a certain use, experience may show that it is also usefulfor other medical problems. Although these uses are not included in productlabeling, tamoxifen is used in certain patients with the following medicalconditions:

• Malignant melanoma (a certain type of skin cancer)
• Cancer of the endometrium (lining of the uterus)

Other than the above information, there is no additionalinformation relating to proper use, precautions, or side effects for theseuses.