Drug interactions
Anastrozole + Desogestrel-ethinyl estradiol
Severity: Major
Anastrozole and Desogestrel-ethinyl estradiol: major 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
Anastrozole works by lowering estrogen levels, and exogenous estrogen such as ethinyl estradiol opposes this effect. The combination undermines the therapeutic aim in hormone-receptor-positive breast cancer, and anastrozole is not intended for use in premenopausal women who might need contraception.
What this interaction means in plain words
Anastrozole and Desogestrel-ethinyl estradiol can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for.
Anastrozole belongs to Oncology; Desogestrel-ethinyl estradiol belongs to Endocrine.
Why it happens
Pharmacodynamic antagonism: exogenous estrogen counteracts aromatase inhibition-induced estrogen suppression.
What to do
Avoid combined estrogen-containing products in patients taking anastrozole; use a non-hormonal contraceptive if contraception is needed.
What to ask your pharmacist
- Does the benefit of taking both outweigh the risk in my case?
- Do I need any blood test, ECG or other check while on both?
- What early warning signs should I watch for, and what should I do if they appear?
Pro+ members
Unlock the full page
Create an account and start a Pro+ trial to unlock the full management advice for Anastrozole and Desogestrel-ethinyl estradiol, the additional notes, the evidence detail and the whole-prescription interaction checker.
- Full clinical management advice
- Additional notes
- Evidence detail
- Interaction checker for a whole prescription
Try Pro+ free for 14 days on the web. No card needed.
Other interactions of Desogestrel-ethinyl estradiol
- Desogestrel-ethinyl estradiol + Fezolinetant Contraindicated
- Aminocaproic acid + Desogestrel-ethinyl estradiol Major
- Amobarbital + Desogestrel-ethinyl estradiol Major
- Apalutamide + Desogestrel-ethinyl estradiol Major
- Atazanavir + Desogestrel-ethinyl estradiol Major
- Belzutifan + Desogestrel-ethinyl estradiol Major
Other interactions of Anastrozole
- Anastrozole + Bazedoxifene / conjugated estrogens Contraindicated
- Anastrozole + Bazedoxifene-conjugated estrogens Contraindicated
- Anastrozole + Conjugated estrogens Contraindicated
- Anastrozole + Estradiol Contraindicated
- Anastrozole + Estrogens conjugated synthetic Contraindicated
- Anastrozole + Estrogens esterified Contraindicated
Frequently asked questions
Can I take Anastrozole with Desogestrel-ethinyl estradiol?
MediHelp rates the interaction as major. Anastrozole and Desogestrel-ethinyl estradiol can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for. Anastrozole works by lowering estrogen levels, and exogenous estrogen such as ethinyl estradiol opposes this effect. The combination undermines the therapeutic aim in hormone-receptor-positive breast cancer, and anastrozole is not intended for use in premenopausal women who might need contraception.
How serious is the interaction between Anastrozole and Desogestrel-ethinyl estradiol?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid combined estrogen-containing products in patients taking anastrozole; use a non-hormonal contraceptive if contraception is needed.
What other medicines interact with Desogestrel-ethinyl estradiol?
MediHelp also lists interactions of Desogestrel-ethinyl estradiol with, for example, Fezolinetant, Aminocaproic acid, Amobarbital. The full list is on the Desogestrel-ethinyl estradiol page.
Full monographs, dosing and an interaction checker in the MediHelp app
Open the complete reference, check multi-drug interactions and use dosing tools in the MediHelp app.
