Drug interactions
Desogestrel-ethinyl estradiol + Letrozole
Severity: Major
Desogestrel-ethinyl estradiol and Letrozole: 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
Letrozole suppresses estrogen synthesis to treat hormone-sensitive breast cancer, and an estrogen-containing contraceptive provides estrogen that opposes this effect. The combination undermines therapy and is not appropriate. Letrozole is used in postmenopausal women, and in premenopausal women it requires ovarian suppression.
What this interaction means in plain words
Desogestrel-ethinyl estradiol and Letrozole 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.
Desogestrel-ethinyl estradiol belongs to Endocrine; Letrozole belongs to Oncology.
Why it happens
Pharmacodynamic antagonism: exogenous estrogen counteracts aromatase inhibition.
What to do
Avoid combining estrogen-containing products with letrozole. Use a non-hormonal contraceptive method when 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?
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Other interactions of Desogestrel-ethinyl estradiol
- Desogestrel-ethinyl estradiol + Fezolinetant Contraindicated
- Aminocaproic acid + Desogestrel-ethinyl estradiol Major
- Amobarbital + Desogestrel-ethinyl estradiol Major
- Anastrozole + Desogestrel-ethinyl estradiol Major
- Apalutamide + Desogestrel-ethinyl estradiol Major
- Atazanavir + Desogestrel-ethinyl estradiol Major
Other interactions of Letrozole
Frequently asked questions
Can I take Desogestrel-ethinyl estradiol with Letrozole?
MediHelp rates the interaction as major. Desogestrel-ethinyl estradiol and Letrozole 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. Letrozole suppresses estrogen synthesis to treat hormone-sensitive breast cancer, and an estrogen-containing contraceptive provides estrogen that opposes this effect. The combination undermines therapy and is not appropriate. Letrozole is used in postmenopausal women, and in premenopausal women it requires ovarian suppression.
How serious is the interaction between Desogestrel-ethinyl estradiol and Letrozole?
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 combining estrogen-containing products with letrozole. Use a non-hormonal contraceptive method when 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.
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