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Anastrozole oral

Updated 2 Feb 2023 | Breast cancer


Tablets containing anastrozole

Drugs List

  • anastrozole 1mg tablets
  • ARIMIDEX 1mg tablets
  • Therapeutic Indications


    Hormone receptor positive, advanced breast cancer in post-menopausal women
    Oestrogen receptor positive early invasive breast cancer-adjunctive therapy
    Postmenopausal ER+ early breast cancer following 2-3yrs tamoxifen therapy

    Treatment of advanced breast cancer in post-menopausal women. Efficacy has not been demonstrated in oestrogen receptor negative patients unless they had a previous positive clinical response to tamoxifen.

    Adjunctive treatment of postmenopausal women with oestrogen receptor positive early invasive breast cancer.

    Adjuvant treatment for early breast cancer in hormone receptor positive post menopausal women who have received 2 to 3 years of adjuvant tamoxifen treatment.

    Unlicensed Uses

    Prevention of breast cancer (postmenopausal women at moderate to high risk)

    Prevention of breast cancer (postmenopausal women at moderate to high risk) initiated under specialist supervision.


    Whilst the doses stated below are those recommended by the manufacturer, local cancer network protocols for the relevant indication should be consulted.


    Treatment (licensed):
    1mg once daily.

    Prevention (unlicensed):
    1mg once daily.

    Patients with Renal Impairment

    Some manufacturer's advise against use in severe renal impairment.



    Precautions and Warnings

    Glucose-galactose malabsorption syndrome
    Hepatic impairment
    Lactose intolerance
    Renal impairment - creatinine clearance below 20ml/minute

    Advise impaired alertness may affect ability to drive or operate machinery
    Do not use in combination with luteinising hormone release hormone analogue
    Not all available brands are licensed for all indications
    Contains lactose
    Consult local policy on the safe use of oral anti-cancer drugs
    Staff: Not to be handled by pregnant staff
    Define menopause biochemically if in doubt about hormonal status
    Investigate persistent or recurrent vaginal bleeding
    Patients at risk of osteoporosis should have bone density assessed
    May cause loss of bone mineral density
    Treatment or prophylaxis of osteoporosis should be started as appropriate
    In early disease the recommended duration of treatment is 5 years

    Women suffering from osteoporosis or at risk of osteoporosis should have their bone density assessed by bone densitometry e.g. DEXA scanning at the initiation of treatment and regularly throughout therapy with anastrozole. Treatment or prophylaxis for osteoporosis should be started as soon as possible and closely monitored. Circulating oestrogen levels are reduced by anastrozole causing a reduction in bone mineral density. Patients may have a higher risk of fracture.

    There are uncommon reports of vaginal bleeding mainly in patients with advanced disease in the weeks after changing from existing hormonal therapy to anastrozole treatment. If persistent, further evaluation should be considered.

    Pregnancy and Lactation


    Anastrozole has no relevant indication in premenopausal women.

    The use of all medication in pregnancy should be avoided whenever possible; particularly in the first trimester. Non-drug treatments should also be considered. When essential, a medication with the best safety record over time should be chosen, employing the lowest effective dose for the shortest possible time. Polypharmacy should be avoided. Teratogens taken in the pre-embryonic period, often quoted as lasting until 14-17 days post-conception, are believed to have an all-or-nothing effect. Where drugs have a short half-life, and when the date of conception is certain, this may allow women to be reassured where drug exposure has occurred within this time frame. Further advice may be available from the UK National Teratology Information Service (NTIS) and through ToxBase, available via password on the internet ( ) or if this is unavailable at the backup site ( ).


    Anastrozole has no relevant indication in premenopausal women.

    Neonates, infants born prematurely, those with low birth weight, those with an unstable gastrointestinal function or who have serious illnesses may require special consideration. For any infant, if a drug is prescribed to the nursing mother, it should be at the lowest practical dose and for the shortest time. When drug administration is unavoidable and breastfeeding is to continue, minimisation of exposure of the infant to the drug may sometimes be achieved by timing the maternal doses to just after a feeding episode. Infants exposed to drugs via breast milk should be monitored for unusual signs or symptoms. Interactions between the drug received by the infant from the mother's milk and medication prescribed for the infant should also be considered, for example, when the drug given to the infant may prevent metabolism of the drug received via breast milk.
    Specialist advice is available from the UK Drugs in Lactation Advisory Service at

    Effects on Ability to Drive and Operate Machinery

    Advise patients that if affected by side effects such as somnolence, they should not drive or operate machinery.

    Side Effects

    Allergic reaction
    Anaphylactoid reaction
    Angina pectoris
    Bone pain
    Carpal tunnel syndrome
    Cerebrovascular accident
    Coronary artery disorder
    Cutaneous vasculitis
    Decrease in bone mineral density
    Deep vein thrombosis (DVT)
    Erythema multiforme
    Gamma glutamyl transferase (GGT) increased
    Hair thinning
    Hot flushes
    Increase in alkaline phosphatase
    Increase in serum ALT/AST
    Increased risk of fractures
    Joint pain
    Mood changes
    Myocardial infarction
    Myocardial ischaemia
    Pulmonary embolism
    Risk of endometrial carcinoma
    Serum bilirubin increased
    Stevens-Johnson syndrome
    Trigger finger
    Vaginal bleeding
    Vaginal discharge
    Vaginal dryness


    It is strongly recommended that the UK National Poisons Information Service be consulted on cases of suspected or actual overdose where there is doubt over the degree of risk or about appropriate management.

    The following number will direct the caller to the relevant local centre (0844) 892 0111

    Information may be obtained if you have access to ToxBase the primary clinical toxicology database of the National Poisons Information Service. This is available via password on the internet ( ) or if this is unavailable at the backup site ( ).

    Further Information

    Last Full Review Date: January 2013

    Reference Sources

    Martindale: The Complete Drug Reference, 37th edition (2011) ed. Sweetman, S. Pharmaceutical Press, London.

    Summary of Product Characteristics: Arimidex 1mg Film-Coated Tablet. AstraZeneca UK Ltd. Revised June 2021.
    Summary of Product Characteristics: Anastrozole 1mg film-coated tablets. Accord. Revised March 2012.
    Summary of Product Characteristics: Anastrozole tablets. Actavis UK ltd. Revised July 2012.
    Summary of Product Characteristics: Anastrozole 1mg film-coated tablets. Medac GmbH. Revised November 2011.
    Summary of Product Characteristics: Anastrozole 1mg film-coated tablets. Sandoz. Revised November 2010.
    Summary of Product Characteristics: Anastrozole tablets. Zentiva. Revised December 2010.
    Summary of Product Characteristics: Nastrosa 1mg film-coated tablets. Discovery Pharmaceuticals. Revised January 2011.

    The Renal Drug Handbook. 3rd edition. (2009) ed. Ashley, C and Currie, Radcliffe Publishing Ltd, Abingdon.

    NICE Evidence Services Available at: Last accessed: 29 March 2018

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    Medscape UK | Univadis prescription drug monographs & interactions are based on FDB Multilex Content

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    FDB Disclaimer : FDB Multilex is intended for the use of healthcare professionals and is provided on the basis that the healthcare professionals will retain FULL and SOLE responsibility for deciding what treatment to prescribe or dispense for any particular patient or circumstance.