Drug interactions
Anastrozole + Ethinyl estradiol-drospirenone
Severity: Major
Anastrozole and Ethinyl estradiol-drospirenone: 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 levels as breast cancer therapy, while the contraceptive provides exogenous estrogen that may oppose this effect. The combination defeats the purpose of therapy.
What this interaction means in plain words
Anastrozole and Ethinyl estradiol-drospirenone 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-drospirenone belongs to Endocrine.
Why it happens
Pharmacodynamic antagonism between exogenous estrogen and aromatase inhibition.
What to do
Avoid estrogen-containing products 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-drospirenone
- Ethinyl estradiol-drospirenone + Fezolinetant Contraindicated
- Ethinyl estradiol-drospirenone + Ombitasvir / paritaprevir / ritonavir Contraindicated
- Ethinyl estradiol-drospirenone + Ombitasvir / paritaprevir / ritonavir and dasabuvir Contraindicated
- Ethinyl estradiol-drospirenone + Tranexamic acid Contraindicated
- Aminocaproic acid + Ethinyl estradiol-drospirenone Major
- Amobarbital + Ethinyl estradiol-drospirenone 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-drospirenone?
MediHelp rates the interaction as major. Anastrozole and Ethinyl estradiol-drospirenone 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 levels as breast cancer therapy, while the contraceptive provides exogenous estrogen that may oppose this effect. The combination defeats the purpose of therapy.
How serious is the interaction between Anastrozole and Ethinyl estradiol-drospirenone?
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 products with anastrozole. Use non-hormonal contraception when needed.
What other medicines interact with Ethinyl estradiol-drospirenone?
MediHelp also lists interactions of Ethinyl estradiol-drospirenone with, for example, Fezolinetant, Ombitasvir / paritaprevir / ritonavir, Ombitasvir / paritaprevir / ritonavir and dasabuvir. The full list is on the Ethinyl estradiol-drospirenone page.
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