Drug interactions
Enzalutamide + Norethisterone
Severity: Major
Enzalutamide and Norethisterone: major interaction.
Last updated Sources: US FDA label
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
Enzalutamide, a strong CYP3A4 inducer, may markedly reduce norethisterone exposure. Contraceptive failure and menstrual irregularities may result.
What this interaction means in plain words
Enzalutamide and Norethisterone 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.
Enzalutamide belongs to Endocrine; Norethisterone belongs to Endocrine.
Why it happens
Enzalutamide induces CYP3A4, increasing norethisterone clearance.
What to do
Use a non-hormonal contraceptive method during treatment and for an appropriate period after. Monitor for loss of effect if norethisterone is used therapeutically.
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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References
Other interactions of Norethisterone
- Acitretin + Norethisterone Contraindicated
- Amobarbital + Norethisterone Major
- Apalutamide + Norethisterone Major
- Belzutifan + Norethisterone Major
- Bosentan + Norethisterone Major
- Brigatinib + Norethisterone Major
Other interactions of Enzalutamide
- Doravirine + Enzalutamide Contraindicated
- Elbasvir / grazoprevir + Enzalutamide Contraindicated
- Ensitrelvir + Enzalutamide Contraindicated
- Enzalutamide + Fostemsavir Contraindicated
- Enzalutamide + Isavuconazonium Contraindicated
- Enzalutamide + Lenacapavir Contraindicated
Frequently asked questions
Can I take Enzalutamide with Norethisterone?
MediHelp rates the interaction as major. Enzalutamide and Norethisterone 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. Enzalutamide, a strong CYP3A4 inducer, may markedly reduce norethisterone exposure. Contraceptive failure and menstrual irregularities may result.
How serious is the interaction between Enzalutamide and Norethisterone?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Use a non-hormonal contraceptive method during treatment and for an appropriate period after. Monitor for loss of effect if norethisterone is used therapeutically.
What other medicines interact with Norethisterone?
MediHelp also lists interactions of Norethisterone with, for example, Acitretin, Amobarbital, Apalutamide. The full list is on the Norethisterone page.
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