Drug interactions
Cenobamate + Norethisterone
Severity: Major
Cenobamate and Norethisterone: major interaction.
Last updated Sources: UK SmPC
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
Cenobamate is a CYP3A4 inducer and can lower norethisterone exposure. This may lead to contraceptive failure or breakthrough bleeding.
What this interaction means in plain words
Cenobamate 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.
Cenobamate belongs to Central Nervous System; Norethisterone belongs to Endocrine.
Why it happens
Induction of CYP3A4 by cenobamate increases norethisterone metabolism.
What to do
Advise additional or alternative non-hormonal contraception while on cenobamate. Do not rely on norethisterone alone for contraception.
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
- Norethisterone 5mg Tablets - SmPC sections 4.3/4.5 (class statement: anticonvulsants; "These compounds include anticonvulsants (e.g., phenobarbital, phenytoin, carbamazepine)") — electronic medicines compendium (UK SmPC)
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 Cenobamate
Frequently asked questions
Can I take Cenobamate with Norethisterone?
MediHelp rates the interaction as major. Cenobamate 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. Cenobamate is a CYP3A4 inducer and can lower norethisterone exposure. This may lead to contraceptive failure or breakthrough bleeding.
How serious is the interaction between Cenobamate 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: Advise additional or alternative non-hormonal contraception while on cenobamate. Do not rely on norethisterone alone for contraception.
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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