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Arimidex 1 mg film-coated tablets – patient leaflet, side effects, dosage

Updated:
Key facts
Status:
Prescription only (POM)
Medicine strength:
1 mg
Contains active substance:
Similar medicines?:

Patient leaflet - Arimidex 1 mg film-coated tablets

1. What Arimidex is and what it is used for.

The name of your medicine is Arimidex 1 mg Film-coated Tablets but will be referred to as Arimidex throughout this leaflet. Arimidex contains a substance called anastrozole. This belongs to a group of medicines called ‘aromatase inhibitors’. Arimidex is used to treat breast cancer in women who have gone through the menopause. Arimidex works by cutting down the amount of the hormone called estrogen that your body makes.

It does this by blocking a natural substance (an enzyme) in your body called ‘aromatase’.

2. What you need to know before you take Arimidex

Do not take Arimidex

  • if you are allergic to anastrozole or any of the other ingredients of this medicine (listed in section 6).
  • if you are pregnant or breast-feeding (see the section called ‘Pregnancy and breast-feeding’).

Do not take Arimidex if any of the above apply to you. If you are not sure, talk to your doctor or pharmacist before taking Arimidex.

Warnings and precautions

Talk to your doctor, or pharmacist or nurse before taking Arimidex

  • if you still have menstrual periods and have not yet gone through the menopause.
  • if you are taking a medicine that contains tamoxifen or medicines that contain estrogen (see the section called ‘Other medicines and Arimidex').
  • if you have ever had a condition that affects the strength of your bones (osteoporosis).
  • if you have problems with your liver or kidneys. If you are not sure if any of the above applies to you, talk to your doctor or pharmacist before taking Arimidex. If you go into the hospital, let the medical staff know you are taking Arimidex.

Other medicines and Arimidex

Tell your doctor or pharmacist if you are taking or have recently taken any other medicines. This includes medicines that you buy without a prescription and herbal medicines. This is because Arimidex can affect the way some medicines work and some medicines can have an effect on Arimidex.

Do not take Arimidex if you are already taking any of the following medicines:

  • Certain medicines used to treat breast cancer (selective estrogen receptor modulators), e.g. medicines that contain tamoxifen. This is because these medicines may stop Arimidex from working properly.
  • Medicines that contain estrogen, such as hormone replacement therapy (HRT).

If this applies to you, ask your doctor

or pharmacist for advice.

Tell your doctor or pharmacist if you are taking the following:

  • A medicine known as an ‘LHRH analogue’. This includes gonadorelin, buserelin, goserelin, leuprorelin and triptorelin. These medicines are used to treat breast cancer, certain female health (gynaecological) conditions, and infertility.

Pregnancy and breast-feeding

Do not take Arimidex if you are pregnant or breast-feeding. Stop Arimidex if you become pregnant and talk to your doctor.

Ask your doctor or pharmacist for advice before taking any medicine.

Driving and using machines

Arimidex is not likely to affect your ability to drive or use any tools or machines. However, some people may occasionally feel weak or sleepy while taking Arimidex. If this happens to you, ask your doctor or pharmacist for advice.

Arimidex contains lactose

Arimidex contains lactose which is a type of sugar. If you have been told by your doctor that you have an intolerance to some sugars, contact your doctor before taking this medicine.

Arimidex Sodium content

This medicine contains less than 1 mmol sodium (23 mg) per tablet, that is to say essentially ‘sodium free’.

3. How to take Arimidex

Always take Arimidex exactly as your doctor or pharmacist has told you. Check with your doctor or pharmacist if you are not sure.

  • The recommended dose is one tablet once a day.
  • Try to take your tablet at the same time each day.
  • Swallow the tablet whole with a drink of water.
  • It does not matter if you take Arimidex before, with or after food.

Keep taking Arimidex for as long as your doctor or pharmacist tells you to. It is a long-term treatment and you may need to take it for several years. Check with your doctor or pharmacist if you are not sure.

Use in children and adolescents

Arimidex should not be given to children and adolescents. If you take more Arimidex than you should

If you take more Arimidex than you should, talk to a doctor straight away.

If you forget to take Arimidex

If you forget to take a dose, just take your next dose as normal.

Do not take a double dose (two doses

at the same time) to make up for a forgotten dose. If you stop taking Arimidex

Do not stop taking your tablets unless your doctor tells you to. If you have any further questions on the use of this medicine, ask your doctor, pharmacist or nurse. Package leaflet: Information for the User

Arimidex® 1 mg film-coated Tablets

(anastrozole)

4. Possible side effects

Like all medicines, this medicine can cause side effects, although not everybody gets them.

Stop taking Arimidex and seek urgent medical treat-ment, if you experience any of the following serious but very rare side effects:

  • An extremely severe skin reaction with ulcers or blisters on the skin. This is known as ‘Stevens-Johnson syndrome’.
  • Allergic (hypersensitivity) reactions with swelling of the throat that may cause difficulty in swallowing or breathing. This is known as ‘angioedema’.

Very common side effects (affect more than 1 in 10 people)

  • Headache.
  • Hot flushes.
  • Feeling sick (nausea).
  • Skin rash.
  • Pain or stiffness in your joints.
  • Inflammation of the joints (arthritis).
  • Feeling weak.
  • Bone loss (osteoporosis).
  • Depression.

Common side effects (affect 1 to 10 people in 100)

  • Loss of appetite.
  • Raised or high levels of fatty substance known as cholesterol in your blood. This would be seen in a blood test.
  • Feeling sleepy.
  • Carpal tunnel syndrome (tingling, pain, coldness, weakness in parts of the hand).
  • Tickling, tingling or numbness of skin, loss/lack of taste. • Diarrhoea.
  • Being sick (vomiting).
  • Changes in blood tests that show how well your liver is working.
  • Thinning of your hair (hair loss).
  • Allergic (hypersensitivity) reactions including face, lips, or tongue.
  • Bone pain.
  • Vaginal dryness.
  • Bleeding from the vagina (usually in the first few weeks of treatment – if the bleeding continues, talk to your doctor).
  • Muscle pain.

Uncommon side effects (affect 1 to 10 people in 1,000)

  • Changes in special blood tests that show how your liver is working (gamma-GT and bilirubin).
  • Inflammation of the liver (hepatitis).
  • Hives or nettle rash.
  • Trigger finger (a condition in which your finger or thumb catches in a bent position).
  • Increased amounts of calcium in your blood. If you experience nausea, vomiting and thirst, you should tell your doctor, or pharmacist or nurse as you may need to have blood tests.

Rare side effects (affect 1 to 10 people in 10,000)

  • Rare inflammation of your skin that may include red patches or blisters.
  • Skin rash caused by hypersensitivity (this can be from allergic or anaphylactoid reaction).
  • Inflammation of the small blood vessels causing red or purple colouring of the skin. Very rarely symptoms of joint, stomach, and kidney pain may occur; this is known as ‘Henoch-Schönlein purpura’.

Effects on your bones

Arimidex lowers the amount of the hormone called estrogen that is in your body. This may lower the mineral content of your bones. Your bones may be less strong and may be more likely to fracture. Your doctor will manage these risks according to treatment guidelines for managing bone health in women who have gone through the menopause.

You should talk to your doctor about the risks and treatment options.

If any of the side effects get serious, or if you notice any side effects not listed in this leaflet, please tell your doctor or pharmacist.

Reporting of side effects

If you get any side effects, talk to your doctor or pharmacist. This includes any possible side effects not listed in this leaflet. You can also report side effects directly via the Yellow Card Scheme at: www.mhra.gov.uk/yel-lowcard or search for MHRA Yellow Card in the Google Play or Apple App Store. By reporting side effects, you can help provide more information on the safety of this medici֯ne.

5. How to store Arimidex

Keep this medicine out of the sight and reach of children.

Keep your tablets in a safe place where children cannot see or reach them. Your tablets could harm them. Do not use this medicine after the expiry date which is stated on the carton and blister strip after ‘EXP’. The expiry date refers to the last day of that month.

Do not store above 30 °C.

Keep your tablets in the container they came in. If this medicine becomes discoloured or shows any other signs of deterioration, please contact your pharmacist who will advise you on what to do.

Do not throw away any medicines via wastewater or household waste. Ask your pharmacist how to throw away medicines you no longer use. These measures will help protect the environment.

6. Contents of the pack and other information

What Arimidex contains

  • The active substance is anastrozole. Each film-coated tablet contains 1 mg of anastrozole.
  • The other ingredients are: lactose monohydrate, povidone, sodium starch glycollate, magnesium stearate, hypromellose, macrogol 300, titanium dioxide. What Arimidex looks like and contents of the pack

White, round, biconvex film-coated tablets of about 6.1 mm marked ‘A’ on one side and ‘Adx1’ on the other side. Arimidex comes in blister packs of 28 tablets. Product Licence Holder and Manufacturer

Procured from within the EU by the Product Licence holder Orifarm UK Ltd., 236 Jubilee House, 3 The Drive, Great Warley, Brentwood, CM13 3FR, UK

Repacked by Orifarm Supply s.r.o., Palouky 1366, 253 01 Hostivice, Czech Republic

Manufactured by

AstraZeneca AB

Gärtunavägen

SE-151 85 Södertälje

Sweden

Arimidex 1 mg Film-coated Tablets

PL 45985/0663

Leaflet revision date: 29/03/2022

Blind or partially sighted? Is this leaflet hard to see or read?

Call +45 63 95 27 00 to obtain the leaflet in a format suitable for you.

POM

About this document

Source: MHRA - Medicines and Healthcare products Regulatory Agency (products.mhra.gov.uk) · Marketing authorisation: PLPI 45985/0663

Last revision stated in the text: 29 March 2022 · MHRA data as of 13 October 2026

What the sections and the side effect frequencies mean: How to read a patient leaflet

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The information on this site does not replace the advice of a doctor or pharmacist.

Facts about Arimidex 1 mg film-coated tablets

What these facts mean

Prescription needed?? Yes, prescription-only medicine (POM)
Active substance? Anastrozole
Strength? 1 mg
Pharmaceutical form? Oral tablet
How is it taken? Oral
Is it available?? Listed as available (NHS Dictionary of Medicines and Devices – not a record of current supplies)
Drug group (ATC)?
  1. L Antineoplastic and immunomodulating agents
    1. L02 Endocrine therapy antineoplastic and immunomodulating agents
      1. L02B Hormone antagonists and related agents
        1. L02BG Aromatase inhibitors
          1. L02BG03 anastrozole
Marketing authorisation? PLPI 45985/0663
Codes? BNF 08030401

Sources: the MHRA product information (products.mhra.gov.uk) and the NHS Dictionary of Medicines and Devices (dm+d), release 11.1.0 of 9 November 2026, NHS Business Services Authority. Contains public sector information licensed under the Open Government Licence v3.0.