Tamoxifen

Name: Tamoxifen

What other information should I know?

  • Keep all appointments with your doctor and the laboratory. Your doctor will order certain lab tests to check your body's response to tamoxifen.
  • Before having any laboratory test, tell your doctor and the laboratory personnel that you are taking tamoxifen.
  • Do not let anyone else take your medication. Talk to your pharmacist if you have any questions about refilling your prescription.

It is important for you to keep a written list of all of the prescription and nonprescription (over-the-counter) medicines you are taking, as well as any products such as vitamins, minerals, or other dietary supplements. You should bring this list with you each time you visit a doctor or if you are admitted to a hospital. It is also important information to carry with you in case of emergencies.

What else should I know about tamoxifen (Soltamox)?

What preparations of tamoxifen (Soltamox) are available?
  • Tablets: 10 and 20 mg. Solution: 10 mg/5 ml
How should I keep tamoxifen (Soltamox) stored?
  • Tamoxifen should be stored in a dry place at 15 C - 30 C (59 F - 86 F).
How does tamoxifen (Soltamox) work?
  • The precise mechanism of its action is unknown, but one possibility is that it binds and blocks estrogen receptors on the surface of cells, preventing estrogens from binding and activating the cell. It is used in patients for treating and preventing breast cancer.
When was tamoxifen (Soltamox) approved by the FDA?
  • Tamoxifen was approved by the FDA in December 1997.

Tamoxifen Overview

Tamoxifen is a prescription medication used to treat breast cancer and lower the the chance of developing breast cancer. Certain types of breast cancers need estrogen to grow. Tamoxifen belongs to a group of drugs called anti-estrogens, which can block estrogen’s effects, slowing the growth of cancer cells. 

This medication comes in a tablet and an oral solution and is usually taken once or twice a day.

Common side effects of tamoxifen include hot flashes and vaginal discharge.

Tamoxifen Interactions

Tell your doctor about all the medicines you take including prescription and non-prescription medicines, vitamins, and herbal supplements. Especially tell your doctor if you take:

  • aminoglutethimide (Cytadren);
  • anastrazole (Arimidex); 
  • bromocriptine (Parlodel);
  • cancer chemotherapy medication such as cyclophosphamide (Cytoxan, Neosar) letrozole (Femara);
  • medroxyprogesterone (Depo-Provera, Provera, in Prempro);
  • phenobarbital;
  • rifampin (Rifadin, Rimactane)

This is not a complete list of tamoxifen drug interactions. Ask your doctor or pharmacist for more information.

Tamoxifen Food Interactions

Medicines can interact with certain foods. In some cases, this may be harmful and your doctor may advise you to avoid certain foods. In the case of tamoxifen there are no specific foods that you must exclude from your diet when receiving tamoxifen.

Other Requirements

  • Have regular gynecology check-ups, breast exams and mammograms. Your doctor will tell you how often. These will check for signs of breast cancer and cancer of the endometrium (lining of the uterus). Because tamoxifen does not prevent all breast cancers, and you may get other types of cancers, you need these exams to find any cancers as early as possible.
  • Tell all of the doctors that you see that you are taking tamoxifen.
  • Tell your doctor right away if you have any new breast lumps.

Tamoxifen tablets:

  • Store tamoxifen at controlled room temperature, 20-25°C (68-77°F).

Tamoxifen Oral Solution:

  • Store at temperatures up to 25°C (77°F).
  • DO NOT freeze or refrigerate.
  • Store in original packaging in order to protect from light. Use within 3 months of opening.

Keep this and all medicines out of reach of children.

Tamoxifen FDA Warning

For Women with Ductal Carcinoma in Situ (DCIS) and Women at High Risk for Breast Cancer: Serious and life-threatening events associated with tamoxifen in the risk reduction setting (women at high risk for cancer and women with DCIS) include uterine malignancies, stroke and pulmonary embolism. Incidence rates for these events were estimated from the NSABP P-1 trial. Uterine malignancies consist of both endometrial adenocarcinoma (incidence rate per 1,000 women-years of 2.20 for tamoxifen vs 0.71 for placebo) and uterine sarcoma (incidence rate per 1,000 women-years of 0.17 for Nolvadex vs 0.04 for placebo)*. For stroke, the incidence rate per 1,000 women-years was 1.43 for Nolvadex vs 1.00 for placebo**. For pulmonary embolism, the incidence rate per 1,000 women-years was 0.75 for tamoxifen versus 0.25 for placebo**.

Some of the strokes, pulmonary emboli, and uterine malignancies were fatal.

Health care providers should discuss the potential benefits versus the potential risks of these serious events with women at high risk of breast cancer and women with DCIS considering tamoxifen to reduce their risk of developing breast cancer.

The benefits of tamoxifen outweigh its risks in women already diagnosed with breast cancer.

*Updated long-term follow-up data (median length of follow-up is 6.9 years) from NSABP P-1 study.

Tamoxifen - Clinical Pharmacology

Tamoxifen citrate is a nonsteroidal agent that has demonstrated potent antiestrogenic properties in animal test systems. The antiestrogenic effects may be related to its ability to compete with estrogen for binding sites in target tissues such as breast. Tamoxifen inhibits the induction of rat mammary carcinoma induced by dimethylbenzanthracene (DMBA) and causes the regression of already established DMBA-induced tumors. In this rat model, Tamoxifen appears to exert its antitumor effects by binding the estrogen receptors.

In cytosols derived from human breast adenocarcinomas, Tamoxifen competes with estradiol for estrogen receptor protein.

Absorption and Distribution:

Following a single oral dose of 20 mg Tamoxifen, an average peak plasma concentration of 40 ng/mL (range 35 to 45 ng/mL) occurred approximately 5 hours after dosing. The decline in plasma concentrations of Tamoxifen is biphasic with a terminal elimination half-life of about 5 to 7 days. The average peak plasma concentration of N-desmethyl Tamoxifen is 15 ng/mL (range 10 to 20 ng/mL). Chronic administration of 10 mg Tamoxifen given twice daily for 3 months to patients results in average steady-state plasma concentrations of 120 ng/mL (range 67 to 183 ng/mL) for Tamoxifen and 336 ng/mL (range 148 to 654 ng/mL) for N-desmethyl Tamoxifen. The average steady-state plasma concentrations of Tamoxifen and N-desmethyl Tamoxifen after administration of 20 mg Tamoxifen once daily for 3 months are 122 ng/mL (range 71 to 183 ng/mL) and 353 ng/mL (range 152 to 706 ng/mL), respectively. After initiation of therapy, steady-state concentrations for Tamoxifen are achieved in about 4 weeks and steady-state concentrations for N-desmethyl Tamoxifen are achieved in about 8 weeks, suggesting a half-life of approximately 14 days for this metabolite. In a steady-state, crossover study of 10 mg Tamoxifen citrate tablets given twice a day vs. a 20 mg Tamoxifen tablet given once daily, the 20 mg Tamoxifen citrate tablet was bioequivalent to the 10 mg Tamoxifen citrate tablets.

Metabolism:

Tamoxifen is extensively metabolized after oral administration. N-desmethyl Tamoxifen is the major metabolite found in patients' plasma. The biological activity of N-desmethyl Tamoxifen appears to be similar to that of Tamoxifen. 4-HydroxyTamoxifen and a side chain primary alcohol derivative of Tamoxifen have been identified as minor metabolites in plasma. Tamoxifen is a substrate of cytochrome P-450 3A, 2C9 and 2D6, and an inhibitor of P-glycoprotein.

Excretion:

Studies in women receiving 20 mg of 14C Tamoxifen have shown that approximately 65% of the administered dose was excreted from the body over a period of 2 weeks with fecal excretion as the primary route of elimination. The drug is excreted mainly as polar conjugates, with unchanged drug and unconjugated metabolites accounting for less than 30% of the total fecal radioactivity.

Special Populations:

The effects of age, gender and race on the pharmacokinetics of Tamoxifen have not been determined. The effects of reduced liver function on the metabolism and pharmacokinetics of Tamoxifen have not been determined.

Pediatric Patients:

The pharmacokinetics of Tamoxifen and N-desmethyl Tamoxifen were characterized using a population pharmacokinetic analysis with sparse samples per patient obtained from 27 female pediatric patients aged 2 to 10 years enrolled in a study designed to evaluate the safety, efficacy, and pharmacokinetics of Tamoxifen in treating McCune-Albright Syndrome. Rich data from two Tamoxifen citrate pharmacokinetic trials in which 59 postmenopausal women with breast cancer completed the studies were included in the analysis to determine the structural pharmacokinetic model for Tamoxifen. A one-compartment model provided the best fit to the data.

In pediatric patients, an average steady-state peak plasma concentration (Css, max) and AUC were of 187 ng/mL and 4110 ng hr/mL, respectively, and Css, max occurred approximately 8 hours after dosing. Clearance (CL/F) as body weight adjusted in female pediatric patients was approximately 2.3-fold higher than in female breast cancer patients. In the youngest cohort of female pediatric patients (2 to 6 year olds), CL/F was 2.6-fold higher; in the oldest cohort (7 to 10.9 year olds) CL/F was approximately 1.9-fold higher. Exposure to N-desmethyl Tamoxifen was comparable between the pediatric and adult patients. The safety and efficacy of Tamoxifen for girls aged 2 to 10 years with McCune-Albright Syndrome and precocious puberty have not been studied beyond one year of treatment. The long-term effects of Tamoxifen therapy in girls have not been established. In adults treated with Tamoxifen an increase in incidence of uterine malignancies, stroke and pulmonary embolism has been noted (see BOXED WARNING).

Drug-Drug Interactions:

In vitro studies showed that erythromycin, cyclosporin, nifedipine and diltiazem competitively inhibited formation of N-desmethyl Tamoxifen with apparent K1 of 20, 1, 45 and 30 µM, respectively. The clinical significance of these in vitro studies is unknown.

Tamoxifen reduced the plasma concentration of letrozole by 37% when these drugs were coadministered. Rifampin, a cytochrome P-450 3A4 inducer reduced Tamoxifen AUC and Cmax by 86% and 55%, respectively. Aminoglutethimide reduces Tamoxifen and N-desmethyl Tamoxifen plasma concentrations. Medroxyprogesterone reduces plasma concentrations of N-desmethyl, but not Tamoxifen.

In the anastrozole adjuvant trial, co-administration of anastrozole and Tamoxifen citrate in breast cancer patients reduced anastrozole plasma concentration by 27% compared to those achieved with anastrozole alone; however, the coadministration did not affect the pharmacokinetics of Tamoxifen or N-desmethylTamoxifen (see PRECAUTIONS-Drug Interactions). Tamoxifen citrate should not be coadministered with anastrozole.

Tamoxifen Dosage and Administration

For patients with breast cancer, the recommended daily dose is 20 to 40 mg. Dosages greater than 20 mg per day should be given in divided doses (morning and evening).

In three single agent adjuvant studies in women, one 10 mg Tamoxifen citrate tablet was administered two (ECOG and NATO) or three (Toronto) times a day for two years. In the NSABP B-14 adjuvant study in women with node-negative breast cancer, one 10 mg Tamoxifen citrate tablet was given twice a day for at least 5 years. Results of the B-14 study suggest that continuation of therapy beyond five years does not provide additional benefit (see CLINICAL PHARMACOLOGY). In the EBCTCG 1995 overview, the reduction in recurrence and mortality was greater in those studies that used Tamoxifen for about 5 years than in those that used Tamoxifen for a shorter period of therapy. There was no indication that doses greater than 20 mg per day were more effective. Current data from clinical trials support 5 years of adjuvant Tamoxifen therapy for patients with breast cancer.

Ductal Carcinoma in Situ (DCIS):

The recommended dose is Tamoxifen citrate tablets 20 mg daily for 5 years.

Reduction in Breast Cancer Incidence in High Risk Women:

The recommended dose is Tamoxifen citrate tablets 20 mg daily for 5 years. There are no data to support the use of Tamoxifen other than for 5 years (see CLINICAL PHARMACOLOGY, Clinical Studies, Reduction in Breast Cancer Incidence in High Risk Women).

How is Tamoxifen Supplied

Tamoxifen Citrate Tablets, USP are available as:
10 mg: Containing 15.2 mg Tamoxifen citrate, an amount equivalent to 10 mg of Tamoxifen. White, round, unscored, biconvex tablet. Debossed with "2232" on one side and "WPI" on the other side.
Available in bottles of:
Unit-of-use 60 Tablets NDC 51862-449-60
Unit-of-use 180 Tablets NDC 51862-449-18

20 mg: Containing 30.4 mg Tamoxifen citrate, an amount equivalent to 20 mg of Tamoxifen. White, round, unscored, biconvex tablet. Debossed with "2233" on one side and "WPI" on the other side.
Available in bottles of:
Unit-of-use 30 Tablets NDC 51862-450-30
Unit-of-use 90 Tablets NDC 51862-450-90

Store at 20° to 25°C (68° to 77°F) [See USP Controlled Room Temperature].
Dispense in a well-closed, light-resistant container. 

For more information about Tamoxifen citrate, call 1-800-344-8661.
Arimidex® is a trademark of AstraZeneca.

MEDICATION GUIDE

Tamoxifen Citrate Tablets, USP

(ta-MOX-I-fen)

Written for women who use Tamoxifen to lower their high chance of getting breast cancer or who have ductal carcinoma in situ (DCIS)

This Medication Guide discusses only the use of Tamoxifen to lower the chance of getting breast cancer in high-risk women and in women treated for DCIS.

People taking Tamoxifen to treat breast cancer have different benefits and different decisions to make than high-risk women or women with ductal carcinoma in situ (DCIS) taking Tamoxifen to reduce the chance of getting breast cancer. If you already have breast cancer, talk with your doctor about how the benefits of treating breast cancer with Tamoxifen compare to the risks that are described in this document.

Why should I read this Medication Guide?

This guide has information to help you decide whether to use Tamoxifen to lower your chance of getting breast cancer.

You and your doctor should talk about whether the possible benefit of Tamoxifen in lowering your high chance of getting breast cancer is greater than its possible risks. Your doctor has a special computer program or hand-held calculator to tell if you are in the high-risk group. If you have DCIS and have been treated with surgery and radiation therapy, your doctor may prescribe Tamoxifen to decrease your chance of getting invasive (spreading) breast cancer.

Read this guide carefully before you start Tamoxifen. It is important to read the information you get each time you get more medicine. There may be something new. This guide does not tell you everything about Tamoxifen and does not take the place of talking with your doctor.

Only you and your doctor can determine if Tamoxifen is right for you.

What is the most important information I should know about using Tamoxifen to reduce the chance of getting breast cancer?

Tamoxifen is a prescription medicine that is like estrogen (female hormone) in some ways and different in other ways. In the breast, Tamoxifen can block estrogen's effects. Because it does this, Tamoxifen may block the growth of breast cancers that need estrogen to grow (cancers that are estrogen- or progesterone-receptor positive).

Tamoxifen can lower the chance of getting breast cancer in women with a higher than normal chance of getting breast cancer in the next five years (high-risk women) and women with DCIS.

Because high-risk women don't have cancer yet, it is important to think carefully about whether the possible benefit of Tamoxifen in lowering the chance of getting breast cancer is greater than its possible risks.

This Medication Guide reviews the risks and benefits of using Tamoxifen to reduce the chance of getting breast cancer in high-risk women and women with DCIS. This guide does not discuss the special benefits and decisions for people who already have breast cancer.

Why do women and men use Tamoxifen?

Tamoxifen has more than one use. Tamoxifen is used:

  1. to lower the chance of getting breast cancer in women with a higher than normal chance of getting breast cancer in the next 5 years (high-risk women).
  2. to lower the chance of getting invasive (spreading) breast cancer in women who had surgery and radiation for ductal carcinoma in situ (DCIS). DCIS means the cancer is only inside the milk ducts.
  3. to treat breast cancer in women after they have finished early treatment. Early treatment can include surgery, radiation, and chemotherapy. Tamoxifen may keep the cancer from spreading to other parts of the body. It may also reduce the woman's chance of getting a new breast cancer.
  4. in women and men, to treat breast cancer that has spread to other parts of the body (metastatic breast cancer).

This guide talks only about using Tamoxifen to lower the chance of getting breast cancer (#1 and #2 above).

What are the benefits of Tamoxifen to lower the chance of getting breast cancer in high-risk women and in women treated for DCIS?

A large U.S. study looked at high-risk women and compared the ones who took Tamoxifen for 5 years with others who took a pill without Tamoxifen (placebo). High-risk women were defined as women who have a 1.7% or greater chance of getting breast cancer in the next 5 years, based on a special computer program. In this study:

  • Out of every 1000 high-risk women who took a placebo, each year about 7 got breast cancer.
  • Out of every 1000 high-risk women who took Tamoxifen, each year about 4 got breast cancer.

The study showed that on average, high-risk women who took Tamoxifen lowered their chances of getting breast cancer by 44%, from 7 in 1000 to 4 in 1000.

Another U.S. study looked at women with DCIS and compared those who took Tamoxifen for 5 years with others who took a placebo. In this study:

  • Out of every 1000 women with DCIS who took placebo, each year about 17 got breast cancer.
  • Out of every 1000 women with DCIS who took Tamoxifen, each year about 10 got breast cancer.

The study showed that on average, women with DCIS who took Tamoxifen lowered their chances of getting invasive (spreading) breast cancer by 43%, from 17 in 1000 to 10 in 1000.

These studies do not mean that taking Tamoxifen will lower your personal chance of getting breast cancer. We do not know what the benefits will be for any one woman who takes Tamoxifen citrate to reduce her chance of getting breast cancer.

What are the risks of Tamoxifen?

In the studies described under "What are the benefits of Tamoxifen?", the high-risk women who took Tamoxifen citrate got certain side effects at a higher rate than those who took a placebo. Some of these side effects can cause death.

In one study, in women who still had their uterus:

  • Out of every 1000 women who took a placebo, each year 1 got endometrial cancer (cancer of the lining of the uterus) and none got uterine sarcoma (cancer of the body of the uterus).
  • Out of every 1000 women who took Tamoxifen, each year 2 got endometrial cancer and fewer than 1 got uterine sarcoma.

These results show that, on average, in high-risk women who still had their uterus, Tamoxifen citrate doubled the chance of getting endometrial cancer from 1 in 1000 to 2 in 1000, and it increased the chance of getting uterine sarcoma. This does not mean that taking Tamoxifen will double your personal chance of getting endometrial cancer or increase your chance of getting uterine sarcoma. We do not know what this risk will be for any one woman. The risk is different for women who no longer have their uterus.

For all women in this study, taking Tamoxifen increased the risk of having a blood clot in their lungs or veins, or of having a stroke. In some cases, women died from these effects.

Tamoxifen increased the risk of getting cataracts (clouding of the lens of the eye) or needing cataract surgery. (See "What are the possible side effects of Tamoxifen?" for more details about side effects.)

What don't we know about taking Tamoxifen citrate to reduce the chance of getting breast cancer?

We don't know:

  • if Tamoxifen lowers the chance of getting breast cancer in women who have abnormal breast cancer genes (BRCA1 and BRCA2)
  • if taking Tamoxifen for 5 years reduces the number of breast cancers a woman will get in her lifetime or if it only delays some breast cancers
  • if Tamoxifen helps a woman live longer
  • the effects of taking Tamoxifen with hormone replacement therapy (HRT), birth control pills, or androgens (male hormones)
  • the benefits of taking Tamoxifen if you are less than 35 years old

Studies are being done to learn more about the long-term benefits and risks of using Tamoxifen to reduce the chance of getting breast cancer.

What are the possible side effects of Tamoxifen?

The most common side effect of Tamoxifen is hot flashes. This is not a sign of a serious problem.

The next most common side effect is vaginal discharge. If the discharge is bloody, it could be a sign of a serious problem. [See "Changes in the lining (endometrium) or body of your uterus" below.]

Less common but serious side effects of Tamoxifen are listed below. These can occur at any time. Call your doctor right away if you have any signs of side effects listed below:

  • Changes in the lining (endometrium) or body of your uterus. These changes may mean serious problems are starting, including cancer of the uterus. The signs of changes in the uterus are:

- Vaginal bleeding or bloody discharge that could be a rusty or brown color. You should call your doctor even if only a small amount of bleeding occurs.

- Change in your monthly bleeding, such as in the amount or timing of bleeding or increased clotting.

- Pain or pressure in your pelvis (below your belly button).

  • Blood clots in your veins or lungs. These can cause serious problems, including death. You may get clots up to 2 to 3 months after you stop taking Tamoxifen citrate. The signs of blood clots are:

- sudden chest pain, shortness of breath, coughing up blood

- pain, tenderness, or swelling in one or both of your legs

  • Stroke. Stroke can cause serious medical problems, including death. The signs of stroke are:

- sudden weakness, tingling, or numbness in your face, arm or leg, especially on one side of your body

- sudden confusion, trouble speaking or understanding

- sudden trouble seeing in one or both eyes

- sudden trouble walking, dizziness, loss of balance or coordination

- sudden severe headache with no known cause

  • Cataracts or increased chance of needing cataract surgery. The sign of these problems is slow blurring of your vision.
  • Liver problems, including jaundice. The signs of liver problems include lack of appetite and yellowing of your skin or whites of your eyes.

These are not all the possible side effects of Tamoxifen. For a complete list, ask your doctor or pharmacist.

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Who should not take Tamoxifen?

Do not take Tamoxifen for any reason if you

  • Are pregnant or plan to become pregnant while taking Tamoxifen or during the 2 months after you stop taking Tamoxifen. Tamoxifen may harm your unborn baby. It takes about 2 months to clear Tamoxifen from your body. To be sure you are not pregnant, you can start taking Tamoxifen while you are having your menstrual period. Or, you can take a pregnancy test to be sure you are not pregnant before you begin.
  • Are breast feeding. We do not know if Tamoxifen can pass through your milk and harm your baby.
  • Have had an allergic reaction to Tamoxifen or to any of its inactive ingredients.

If you get pregnant while taking Tamoxifen, stop taking it right away and contact your doctor. Tamoxifen may harm your unborn baby.

Do not take Tamoxifen to lower your chance of getting breast cancer if:

  • You ever had a blood clot that needed medical treatment.
  • You are taking medicines to thin your blood, like warfarin, (also called Coumadin®*).
  • Your ability to move around is limited for most of your waking hours.
  • You are at risk for blood clots. Your doctor can tell you if you are at high risk for blood clots.
  • You do not have a higher than normal chance of getting breast cancer. Your doctor can tell you if you are a high-risk woman.

How should I take Tamoxifen?

  • Swallow the tablet(s) whole, with water or another non-alcoholic liquid. You can take Tamoxifen with or without food. Take your medicine every day. It may be easier to remember if you take it at the same time each day.
  • If you forget a dose, take it when you remember, then take the next dose as usual. If it is almost time for your next dose or you remember at your next dose, do not take extra tablets to make up the missed dose.
  • Take Tamoxifen for 5 years, unless your doctor tells you otherwise.

What should I avoid while taking Tamoxifen?

  • Do not become pregnant while taking Tamoxifen or for 2 months after you stop. Tamoxifen can stop hormonal birth control methods from working. Hormonal methods include birth control pills, patches, injections, rings and implants. Therefore, while taking Tamoxifen, use birth control methods that don't use hormones, such as condoms, diaphragms with spermicide, or plain IUD's. If you get pregnant, stop taking Tamoxifen right away and call your doctor.
  • Do not breastfeed. We do not know if Tamoxifen can pass through your milk and if it can harm the baby.

What should I do while taking Tamoxifen?

  • Have regular gynecology check-ups ("female exams"), breast exams and mammograms. Your doctor will tell you how often. These will check for signs of breast cancer and cancer of the endometrium (lining of the uterus). Because Tamoxifen does not prevent all breast cancers, and you may get other types of cancers, you need these exams to find any cancers as early as possible.
  • Because Tamoxifen can cause serious side effects, pay close attention to your body. Signs you should look for are listed in "What are the possible side effects of Tamoxifen?"
  • Tell all of the doctors that you see that you are taking Tamoxifen.
  • Tell your doctor right away if you have any new breast lumps.

General information about the safe and effective use of Tamoxifen.

Medicines are sometimes prescribed for purposes other than those listed in a Medication Guide. Your doctor has prescribed Tamoxifen only for you. Do not give it to other people, even if they have a similar condition, because it may harm them. Do not use it for a condition for which it was not prescribed.

This Medication Guide is a summary of information about Tamoxifen for women who use Tamoxifen to lower their high chance of getting breast cancer or who have DCIS. If you want more information about Tamoxifen, ask your doctor or pharmacist. They can give you information about Tamoxifen that is written for health professionals. For more information about Tamoxifen or breast cancer, call 1-800-344-8661.

Ingredients: Tamoxifen citrate, croscarmellose sodium, lactose monohydrate, magnesium stearate, microcrystalline cellulose, and pregelatinized starch.

*Coumadin® is a registered trademark of Bristol-Myers Squibb Pharmaceuticals.

This Medication Guide has been approved by the U.S. Food and Drug Administration.

Manufactured by:
Actavis Laboratories FL, Inc.
Fort Lauderdale, FL 33314 USA

Distributed by:
Mayne Pharma
Greenville, NC 27834

Revised: February 2016

Brand Names U.S.

  • Soltamox

Pharmacologic Category

  • Antineoplastic Agent, Estrogen Receptor Antagonist
  • Selective Estrogen Receptor Modulator (SERM)

Use Labeled Indications

Treatment of metastatic (female and male) breast cancer; adjuvant treatment of breast cancer after primary treatment with surgery and radiation; reduce risk of invasive breast cancer in women with ductal carcinoma in situ (DCIS) after surgery and radiation; reduce the incidence of breast cancer in women at high risk

Tamoxifen dosing information

Usual Adult Dose for Breast Cancer:

For the treatment of metastatic breast cancer in women and men:
20 to 40 mg orally Dosages greater than 20 mg should be given in divided doses (morning and evening).

For the treatment of women with Ductal Carcinoma in Situ, following breast surgery and radiation:
20 mg orally daily for 5 years.

To reduce the incidence of breast cancer in women at high risk for breast cancer:
20 mg orally daily for 5 years.

Usual Adult Dose for Breast Cancer - Adjuvant:

For the treatment of node-positive breast cancer in postmenopausal women following total mastectomy or segmental mastectomy, axillary dissection, and breast irradiation:
10 mg orally 2 to 3 times a day for 5 years.

Usual Adult Dose for Breast Cancer - Palliative:

10 to 20 mg orally twice a day

A beneficial response may not be evident for several months after initiation of therapy.

Usual Pediatric Dose for McCune-Albright Syndrome:

For use in girls age 2 to 10 years with McCune-Albright Syndrome and precocious puberty:
20 mg once a day. The duration of treatment is up to 12 months.

Usual Pediatric Dose for Precocious Puberty:

For use in girls age 2 to 10 years with McCune-Albright Syndrome and precocious puberty:
20 mg once a day. The duration of treatment is up to 12 months.

Renal Dose Adjustments

Data not available

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