TAMOXIFEN

COMMON BRAND NAME(S): Nolvadex, Soltamox

GENERIC NAME(S): TAMOXIFEN CITRATE

 

Description: Tamoxifen, a triphenylethylene derivative, that competes with estrogen in order to stop or slow down production of cancer cells.

Pharmacokinetics:

Absorption: Well absorbed from the GIT; peak plasma concentrations after 4-7 hr (oral).

Distribution: Distributed into uterus (high concentrations), endometrial and breast tissues. Protein-binding: Extensive.

Metabolism: Extensively metabolised in liver by the cytochrome P450 isoenzymes CYP3A4, CYP2C9, and CYP2D6, converted to desmethyltamoxifen; undergoes enterohepatic recycling.

Excretion: Faeces (as conjugates), urine (small amounts); 7 days (terminal half-life).

Tamoxifen treats breast cancer that has spread to other parts of the body (metastatic breast cancer), in certain patients after surgery and radiation therapy, and reduce the chances of breast cancer in high-risk patients. This medication blocks the growth of breast cancer by interfering with the effects of estrogen in the breast tissue.

How to use tamoxifen

Read the Medication Guide provided by your pharmacist before you start using tamoxifen and each time you get a refill. If you have any questions, consult your doctor or pharmacist.

Take this medication by mouth with or without food, usually once or twice daily for 5 years, or as directed by your doctor. Daily dosages greater than 20 milligrams are usually divided in half and taken twice a day, in the morning and evening, or as directed by your doctor. If you are using the liquid, measure the dose carefully using a special measuring device/spoon. Do not use a household spoon because you may not get the correct dose.

Dosage is based on your medical condition and response to therapy.

Use this medication regularly to get the most benefit from it. To help you remember, take it at the same time(s) each day.

If you have breast cancer that has spread to other parts of the body, you may experience increased bone/cancer pain and/or disease flare-up as you start taking tamoxifen. In some cases, this may be a sign of a good response to the medication. Symptoms include increased bone pain, increased tumor size, or even new tumors. These symptoms usually disappear quickly. In any case, report these symptoms immediately to your doctor.

Since this drug can be absorbed through the skin and lungs, women who are pregnantor who may become pregnant should not handle this medication or breathe the dust from the tablets. (See also Precautions section.)

Inform your doctor immediately if your condition worsens (e.g., you get new breast lumps).

Tamoxifen has rarely caused very serious (possibly fatal) strokes, blood clots in thelungs/legs, and cancer of the uterus.

Notify your doctor promptly if these effects persist or worsen:

  • hot flashes
  • nausea
  • leg cramps
  • muscle aches
  • hair thinning
  • headache
  • numb/tingling skin
  • loss of sexual ability/interest in men

Tell your doctor immediately if any of these unlikely but serious side effects occur:

  • vision changes (e.g., blurred vision)
  • eye pain
  • easy bruising/bleeding
  • mental/mood changes
  • swelling of ankles/feet
  • unusual tiredness

Tell your doctor immediately if any of these rare but very serious side effects occur:

  • stomach/abdominal pain
  • persistent nausea/vomiting
  • dark urine
  • yellowingeyes/skin
  • signs of infection (e.g., fever, persistent sore throat)

A very serious allergic reaction to this drug is rare.

This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.

Precautions:

  • Allergic reaction to this medication
  • Patitents with a history of blood clots (e.g., deep vein thrombosis, pulmonary embolism, stroke) or conditions that require treatment with a “blood thinner” (such as warfarin)
  • Patients with medical history of:
    • high cholesterol/triglycerides
    • limited or no ability to walk (immobility)
    • diabetes
    • high blood pressure
    • smoking
    • cataracts
    • liver disease
  • Tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products) before having surgery
  • This medication is not recommended for use during pregnancy
  • Consult your doctor before breast-feeding

Consult your doctor regarding the precautions mentioned above.

Interactions:

This drug should not be used with anastrozole or letrozole because very serious interactions may occur.

Tell your doctor or pharmacist of all prescription and nonprescription drugs you may use, especially of:

  • “blood thinners” (e.g., warfarin)
  • estrogens
  • hormonal forms of birth control (e.g., birth control pills, patches, implants)
  • phenobarbital
  • rifamycins (e.g., rifampin)
  • St John’s wort

Other medications may affect how tamoxifen works. Examples include cimetidine, SSRI antidepressants such as fluoxetine/paroxetine, among others.

This medication may interfere with certain laboratory tests (including thyroid tests), possibly causing false test results.

This document does not contain all possible interactions. Therefore, before using this product, tell your doctor or pharmacist of all the products you use. Keep a list of all your medications with you, and share the list with your doctor and pharmacist.

Overdose:

If overdose is suspected, contact a poison control center or emergency room immediately. Symptoms of overdose may include: shaking, unsteady walking, fainting, irregular heartbeat.

Notes

Laboratory and/or medical tests (e.g., blood counts, liver function tests, pelvic exams, mammogram, eye exams) should be performed periodically to monitor your progress or check for side effects. Consult your doctor for more details.

Missed Dose

If you miss a dose, take it as soon as you remember. If it is near the time of the next dose, skip the missed dose and resume your usual dosing schedule. Do not double the dose to catch up.

Storage

Store at room temperature away from light and moisture. Do not store in the bathroom.

If you are using the liquid, do not refrigerate or freeze it. After you open the bottle, discard any unused liquid after 3 months.

Keep all medications away from children and pets.

Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company for more details about how to safely discard your product.

Brands:

Available Brands

  • Fenahex [ Sandoz ]
  • Gynatam [ Fresenius Kabi ]
  • Gyraxen [ Korea United Pharma ]
  • MPL Tamoxil [ MPL ]
  • Tamoplex [ Pharmachemie ]
  • Zitazonium [ Egis ]

Also marketed as

  • Biomedis Tamoxifen [ Biomedis Oncology ]
  • Medtax [ Huons ]
  • Nolvadex-D [ AstraZeneca ]
  • Xifen [ Naprod ]

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