Tamoxifen    

Brand name: Nolvadex ^®  

Generic name:Tamoxifen    

Therapeutic Class: antiestrogen  

Manufacturer / Distributor: AstraZeneca 

Availability:  Tamoxifen is available by prescription only  

FDA Approval: TAMOXIFEN(R) (tamoxifen citrate) was approved by the U.S. Food and Drug Administration (FDA) in October 1998 for the treatment of certain breast cancers in men and women. 

Indications: Tamoxifen is an antiestrogen; it is used to treat certain forms of breast cancer in men and women, mainly: 

·          Metastatic breast cancer -  breast cancer that has spread to other parts of the body;  

·          Non metastatic breast cancer that was previously treated with surgery, radiation, and/or chemotherapy.  

Tamoxifen is used as a preventive treatment in people who are at high risk for developing breast cancer. Tamoxifen is also used to prevent complication in women who have had ductal carcinoma in situ (DCIS).  

Tamoxifen is sometimes prescribed to treat ovulation problems in women who want to get pregnant but are unable to produce eggs. In addition, the medication can be used in the treatment of McCune-Albright syndrome, a genetic disease that affects the bones and color (pigmentation) of the skin in children. 

Dosage form: Tamoxifen comes as white coated  tablet to be taken by mouth 

Dosage:  to prescribe you an effective dosage of Tamoxifen, many criteria will be taken in considerations: your age, health status, and your body surface area (BSA).  In addition, taking other medications as well as the severity of the cancer can play a role in the choice of the treatment. Having this information, your oncologist will recommend you an effective dosage able to combat the disease. Follow the indications of your health care provider or the directions on the prescription label carefully.  

Usually, the recommended daily dosage of  Tamoxifen is 20 to 40 mg in single or multiple doses, before, with or after meals. In the case of adjuvant therapy, the recommended dose is 20 mg per day, for a period of 5 years. In the treatment of advanced cancer, daily doses are between 20 and 40 mg, taken once or twice a day. Do not take less or more of the medication.  

Used water, natural juice or any non-alcoholic drink to swallow Tamoxifen tablets; do not chew or crush them. It is better to take Tamoxifen around the same time every day. It is very important that you take the pills as directed by your physician or pharmacist. Do not change the prescribed dosage or interrupt the treatment without first talking to your doctor.  

Storage:  keep Tamoxifen tightly closed in the container it came, out of the reach of children. Store it at room temperature (15-25 ° C), away from heat, light and moisture. Tamoxifen and all other drugs should not be used beyond the expiration date printed on the container.   

Overdose:  Tamoxifen overdose can be fatal. The risk is even higher when the drug is overdosed for a long term. In fact, most chemotherapy drugs overdose, including Tamoxifen, can lead to death. Even in the absence of overdose, Tamoxifen can cause strokes, blood clots in the lungs, and cancer of the uterus. It is extremely important that you take Tamoxifen as indicated by your health care provider or according to the directions on the label.  

Missing dose: do your best to take Tamoxifen around the same time every day.  In case you forget to take a dose, take the missed one as soon as you remember it. However, if it is almost time for your next dose,  do not double the next dose to recover the missed one; it can be dangerous. Contact your doctor or wait to go back to your regular schedule.   Misusing Tamoxifen can cause life threatening health problems.   

Contraindication:  Tamoxifen   is contraindicated in the following conditions:  

• children   
• women who are breast-feeding   
• blood disease  
• cataract   
• Elderly (unless under strict medical supervision).    

Note :  during the therapy, it is important that you keep all appointments with your doctor and laboratory for regular medical examinations, especially cardiologic and gynecologic exams. Regular checkups help your physician to detect early signs of cancer of the uterus or/and heart problems related to Tamoxifen.  

Mechanism of action (MOA): Tamoxifen is an antiestrogen; it slows or stops the multiplication of cancer cells by blocking the hormonal effects of estrogen in the body.  

Interactions:   talk to your doctor before taking prescriptions and non-prescription substances such as aspirin, vitamins, nutritional supplements, and St. John's Wort. Some medicines may interact with Tamoxifen. Tell your doctor and pharmacist if you are taking any of these medications:  

• Warfarin (Coumadin)  
• Bupropion (Wellbutrin, Zyban)  
• Carbamazepine (Equetro, Tegretol)  
• Cyclophosphamide (Cytoxan, Neosar)  
• Dexamethasone  
• Doxorubicin (Doxil, Adriamycin)  
• Efavirenz (Sustiva)  
• Ifosfamide  
• Irinotecan (Camptosar)  
• Methadone (Dolophine, Methadose)  
• Phenobarbital  
• Phenytoin (Dilantin, Phenytek)  
• Rifampin (Rifadin, Rimactane). 

Side effects: Tamoxifen not only attack cancer cells but also healthy cells, which often leads to adverse reactions in most patients. Common Tamoxifen side effects include:     

• hair loss
• tumor pain 
• hot flashes
• depression  
• weight loss 
• constipation 
• nausea and vomiting   
• excessive tiredness  
• headache and dizziness 
• stomach pain or cramps  
• loss of sexual desire or ability (in men)  

If the side effects above persist for weeks, contact your oncologist. In addition, contact your doctor immediately if you experience any of these symptoms:  

• yellowing of the skin or eyes  
• unusual bruising or bleeding  
• vision problems 
• decreased of appetite  
• mouth sores   
• fever  
• persistent thirst 
• muscle weakness  
• restlessness  
• Swelling of the eyes, face, lips, tongue, throat, hands, arms, feet, ankles, or lower legs.   

References 

1 - encyclopedia.com, document 1G1-63065744 

2 - nlm.nih.gov, Tamoxifen