Tamosin Tablets (sex hormones and other reproductive system medicines)

Tamosin Tablets (sex hormones and other reproductive system medicines) is a brand of medicine containing the active ingredient tamoxifen (sex hormones and other reproductive system medicines).

Find out more about active ingredients.

Consumer medicine information (CMI) leaflet

Developed by the pharmaceutical company responsible for this medicine in Australia, according to TGA regulations.


Tamoxifen Tablets (Ta MOX i fen)

Consumer Medicine Information

What is in this leaflet

This leaflet answers some common questions about TAMOSIN. It does not contain all of the available information.

It does not take the place of talking to your doctor or pharmacist.

All medicines have risks and benefits. Your doctor has weighed the risks of you taking TAMOSIN against the benefits they expect it will have for you.

If you have any concerns about taking this medicine, ask your doctor or pharmacist.

Keep this leaflet with the medicine. You may need to read it again.

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What TAMOSIN is used for

TAMOSIN tablets contain an active ingredient called tamoxifen.

Tamoxifen is an anti-oestrogen medicine.

Tamoxifen is used to counteract the actions of the naturally occurring hormone, oestrogen.

TAMOSIN is used in the treatment of breast cancer.

In some types of breast cancer, oestrogen helps the cancer cells grow. By blocking oestrogen, TAMOSIN may slow or stop the growth of cancer.

Your doctor may have prescribed TAMOSIN for another reason.

Ask your doctor if you have any questions about why this medicine has been prescribed for you.

This medicine is only available with a doctor's prescription.

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Before you take TAMOSIN

When you must not take it

Do not take TAMOSIN if:

  • you have had an allergic reaction to tamoxifen
  • you are allergic to any of the other ingredients listed at the end of this leaflet
  • you are using tamoxifen in combination with coumarin type anticoagulants (e.g. warfarin) as an increase in the anticoagulant effect may occur. Where co-administration is initiated by your Doctor, careful monitoring is required.

Some of the symptoms of an allergic reaction may include shortness of breath, wheezing or difficulty breathing; swelling of the face, lips, tongue or other parts of the body; rash, itching or hives on the skin.

Do not take TAMOSIN if you are pregnant. It may affect your developing baby if you take it during pregnancy.

Do not take TAMOSIN after the expiry date printed on the pack.

Do not take TAMOSIN if the packaging is torn or shows signs of tampering or if the tablets do not look quite right.

Before you start to take it

You must tell your doctor if:

  • You have allergies to any other medicines, foods, preservatives or dyes.
  • You are pregnant or plan to become pregnant.
  • you are also taking coumarin type anticoagulants (e.g. warfarin)

Taking TAMOSIN during pregnancy can harm your developing baby. Your doctor will discuss the risks involved.

  • You are breast-feeding or plan to breast-feed.

Your doctor will discuss the risks and benefits involved in taking TAMOSIN when breast-feeding.

  • You have not been through menopause.

If it is possible that you could become pregnant, you must use a non-hormonal barrier method of contraception, while you are taking TAMOSIN and for two months after you stop taking TAMOSIN.

Tell your doctor if you have or have had any of the following medical conditions:

  • liver problems
  • blood clots in legs, lungs, heart or brain
  • blood disorders i.e. a low platelet count or a low white blood cell count

If you have not told your doctor about any of the above, tell them before you start taking TAMOSIN.

Taking other medicines

Tell your doctor if you are taking any other medicines, including any that you buy without a prescription from a pharmacy, supermarket or health food shop. Some medicines and TAMOSIN may interfere with each other. These include:

  • coumarin type anticoagulants used to prevent blood clots, such as warfarin

This medicine may be affected by TAMOSIN or may affect how well it works.

If you are not sure whether you are taking any of these medicines, check with your doctor or pharmacist.

Your doctor and pharmacist have more information on medicines to be careful with or avoid while taking TAMOSIN.

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How to take TAMOSIN

Follow all the directions given to you by your doctor or pharmacist carefully. They may differ from the information contained in this leaflet.

How much to take

The usual dose of TAMOSIN tablets is from 20 mg to 40 mg (one or two tablets) daily.

Your doctor will advise you on what your dose will be.

How to take it

Swallow the tablets whole with a full glass of water.

When to take it

Take TAMOSIN at about the same time each day.

It does not matter if you take TAMOSIN before or after food.

How long to take it

Keep taking TAMOSIN for as long as your doctor recommends.

If you forget to take it

If it is almost time for your next dose, skip the dose you missed and take your next dose when you are meant to.

Otherwise, take it as soon as you remember, and then go back to taking your medicine as you would normally.

Do not take a double dose to make up for the dose that you missed.

If you are not sure what to do, ask your doctor or pharmacist.

If you take too much (Overdose):

Immediately telephone your doctor or the Poisons Information Centre (phone 13 11 26) for advice, or go to Accident and Emergency at your nearest hospital, if you think that you or anyone else may have taken too much TAMOSIN. Do this even if there are no signs of discomfort or poisoning. You may need urgent medical attention.

Keep telephone numbers for these places handy.

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While you are taking TAMOSIN

Things you must do

Before starting any new medicine, tell your doctor or pharmacist that you are taking TAMOSIN.

Tell any other doctors, dentists and pharmacists that are treating you that you are taking TAMOSIN.

If you become pregnant while taking TAMOSIN, or within two months of stopping treatment, tell your doctor immediately.

Tell your doctor immediately if you notice any unusual vaginal bleeding or discharge.

Tell your doctor immediately if you notice any changes to your eyesight, or any symptoms of blood disorders such as unusual bruising or bleeding

If you are about to have any blood tests, tell your doctor that you are taking TAMOSIN. It is very important to keep all of your doctor's appointments, so that your progress can be checked.

Things you must not do

Do not take TAMOSIN to treat any other complaints unless your doctor tells you to.

Do not give TAMOSIN to anyone else, even if they have the same condition as you.

Do not stop taking TAMOSIN or lower the dosage without checking with your doctor.

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Side effects

Tell your doctor or pharmacist as soon as possible if you do not feel well while you are taking TAMOSIN. Like all other medicines, TAMOSIN may have unwanted side effects in some people. Sometimes they are serious, most of the time they are not. You may need medical treatment if you get some of the side effects.

Do not be alarmed by this list of possible side effects.

You may not experience any of them.

Ask your doctor or pharmacist to answer any questions you may have.

Tell your doctor if you notice any of the following and they worry you:

  • hot flushes
  • nausea, vomiting or stomach upset
  • headache
  • skin rash, itching
  • dizziness or lightheadedness
  • depression
  • swelling of your hands, feet or ankles
  • itching around the vagina or genitals

Tell your doctor immediately if you notice any of the following:

  • problems with your eyesight
  • unusual vaginal bleeding or discharge
  • changes in your menstrual periods
  • unusual bruising or bleeding
  • pain in the bones or at the site of your cancer
  • yellowing of the skin and/or eyes
  • frequent infections such as fever, severe chills, sore throat or mouth ulcers
  • increase in blood calcium levels, therefore you may notice this as nausea, vomiting and excessive thirst

Cases of optic nerve diseases have been reported in patients receiving tamoxifen and, in a small number of cases, blindness has occurred

If you have any unusual vaginal bleeding or other gynaecological symptoms (such as pelvic pain or pressure) when you are taking TAMOSIN or anytime afterwards, tell your doctor. This is because a number of changes to the lining of the womb (endometrium) may occur, some of which may be serious and could include cancer.

Increased risk of blood clots and ovarian cysts (in premenopausal women) have been seen with TAMOSIN

Rarely an increased level of triglycerides (increased levels of fats in the blood) sometimes with pancreatitis (pain or tenderness in the upper abdomen) has been seen with TAMOSIN.

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After using TAMOSIN


Keep your tablets in the bottle until it is time to take them.

Keep your tablets in a cool dry place where the temperature stays below 30°C. Protect from light.

Do not store TAMOSIN or any other medicine in the bathroom or near a sink.

Do not leave it on a windowsill or in the car. Heat or dampness can destroy some medicines.

Keep it where children cannot reach it. A locked cupboard at least one-and-a-half metres above the ground is a good place to store medicines.


If your doctor tells you to stop taking this medicine or the expiry date has passed, ask your pharmacist what to do with any medicine left over.

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Product Description

What it looks like

TAMOSIN tablets are round white tablets with "20" embossed on one side. They are available in plastic bottles containing 60 tablets.


Each TAMOSIN tablet contains the active ingredient tamoxifen citrate, equivalent to 20 mg of tamoxifen.

TAMOSIN tablets also contain the following inactive ingredients:

  • maize starch
  • lactose
  • povidone
  • sodium starch glycollate
  • magnesium stearate

TAMOSIN tablets contain lactose but are gluten and sucrose free.

The Australian Registration Number for TAMOSIN is AUST R 43527.

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Sigma Pharmaceuticals (Australia) Pty Ltd

(A.C.N. 004 118 594)
Locked Bag 268
(96 Merrindale Drive)
Croydon South Vic. 3136
(03) 9839 2800

Date of preparation: July 1996. Revised in August 1998, June 2000. Updated in November 2001, Oct 2005 and March 2007

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CMI provided by MIMS Australia, December 2014  

Related information - Tamosin Tablets (sex hormones and other reproductive system medicines)


04 Dec 2013 Information on medicines available in Australia containing tamoxifen (sex hormones and other reproductive system medicines), including our latest evidence-based information and resources for health professionals and consumers. The active ingredient is the chemical in a medicine that makes it work. Medicines that contain the same active ingredient can be available under more than one brand name. Brands include both active ingredients and inactive ingredients. You'll find information about brands of medicines that contain tamoxifen (sex hormones and other reproductive system medicines) below, including their consumer medicine information (CMI) leaflets.