Drug interactions
Anastrozole + Conjugated estrogens
Severity: Contraindicated
Anastrozole and Conjugated estrogens: contraindicated interaction.
Last updated
For healthcare professionals — reference only. This page is a brief summary, not medical advice and not a substitute for official labeling or clinical judgement. Always verify before prescribing or dispensing.
Summary
Conjugated estrogens replace the estrogen that anastrozole is intended to suppress. This may undermine breast cancer treatment.
What this interaction means in plain words
Anastrozole and Conjugated estrogens are not normally used together. Taking them at the same time is expected to cause harm or make one of them unsafe, so a different medicine is usually chosen for one of the two.
Why it happens
Pharmacodynamic antagonism: exogenous estrogen counteracts aromatase inhibition.
What to do
Avoid the combination. Offer non-hormonal management of menopausal symptoms.
What to ask your pharmacist
- Is there an alternative to one of these two medicines for me?
- If both are essential, who is monitoring me and how often?
- Which symptoms mean I should stop and seek help straight away?
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Other interactions of Anastrozole
- Anastrozole + Bazedoxifene / conjugated estrogens Contraindicated
- Anastrozole + Bazedoxifene-conjugated estrogens Contraindicated
- Anastrozole + Estradiol Contraindicated
- Anastrozole + Estrogens conjugated synthetic Contraindicated
- Anastrozole + Estrogens esterified Contraindicated
- Anastrozole + Estropipate Contraindicated
Frequently asked questions
Can I take Anastrozole with Conjugated estrogens?
MediHelp rates the interaction as contraindicated. Anastrozole and Conjugated estrogens are not normally used together. Taking them at the same time is expected to cause harm or make one of them unsafe, so a different medicine is usually chosen for one of the two. Conjugated estrogens replace the estrogen that anastrozole is intended to suppress. This may undermine breast cancer treatment.
How serious is the interaction between Anastrozole and Conjugated estrogens?
MediHelp rates it contraindicated, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid the combination. Offer non-hormonal management of menopausal symptoms.
What other medicines interact with Anastrozole?
MediHelp also lists interactions of Anastrozole with, for example, Bazedoxifene / conjugated estrogens, Bazedoxifene-conjugated estrogens, Estradiol. The full list is on the Anastrozole page.
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