Drug interactions
Anastrozole + Ethinyl estradiol-norgestimate
Severity: Major
Anastrozole and Ethinyl estradiol-norgestimate: 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 lowers estrogen in postmenopausal women with breast cancer, and estrogen-containing products oppose that effect. Combined use may reduce anticancer benefit.
What this interaction means in plain words
Anastrozole and Ethinyl estradiol-norgestimate 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; Ethinyl estradiol-norgestimate belongs to Endocrine.
Why it happens
Exogenous estrogen counteracts estrogen suppression from aromatase inhibition.
What to do
Avoid estrogen-containing contraceptives with anastrozole. Use non-hormonal contraception when 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?
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Other interactions of Ethinyl estradiol-norgestimate
- Ethinyl estradiol-norgestimate + Fezolinetant Contraindicated
- Ethinyl estradiol-norgestimate + Ombitasvir / paritaprevir / ritonavir and dasabuvir Contraindicated
- Ethinyl estradiol-norgestimate + Tranexamic acid Contraindicated
- Aminocaproic acid + Ethinyl estradiol-norgestimate Major
- Amobarbital + Ethinyl estradiol-norgestimate Major
- Apalutamide + Ethinyl estradiol-norgestimate 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 Ethinyl estradiol-norgestimate?
MediHelp rates the interaction as major. Anastrozole and Ethinyl estradiol-norgestimate 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 lowers estrogen in postmenopausal women with breast cancer, and estrogen-containing products oppose that effect. Combined use may reduce anticancer benefit.
How serious is the interaction between Anastrozole and Ethinyl estradiol-norgestimate?
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 estrogen-containing contraceptives with anastrozole. Use non-hormonal contraception when needed.
What other medicines interact with Ethinyl estradiol-norgestimate?
MediHelp also lists interactions of Ethinyl estradiol-norgestimate with, for example, Fezolinetant, Ombitasvir / paritaprevir / ritonavir and dasabuvir, Tranexamic acid. The full list is on the Ethinyl estradiol-norgestimate page.
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