Drug interactions
Mavacamten + Norethisterone
Severity: Major
Mavacamten and Norethisterone: 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
Mavacamten may induce CYP3A4 and lower progestin exposure. This can cause contraceptive failure or breakthrough bleeding, and mavacamten is associated with fetal risk.
What this interaction means in plain words
Mavacamten 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.
Mavacamten belongs to Cardiovascular; Norethisterone belongs to Endocrine.
Why it happens
Mavacamten induces CYP3A4, increasing the metabolism of norethisterone.
What to do
Use a contraceptive method not affected by enzyme induction, such as an intrauterine system, or add condoms. Continue this for 4 months after the last mavacamten dose.
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 Norethisterone
- Acitretin + Norethisterone Contraindicated
- Amobarbital + Norethisterone Major
- Apalutamide + Norethisterone Major
- Belzutifan + Norethisterone Major
- Bosentan + Norethisterone Major
- Brigatinib + Norethisterone Major
Other interactions of Mavacamten
- Apalutamide + Mavacamten Contraindicated
- Carbamazepine + Mavacamten Contraindicated
- Clarithromycin + Mavacamten Contraindicated
- Dexlansoprazole + Mavacamten Contraindicated
- Efavirenz + Mavacamten Contraindicated
- Enzalutamide + Mavacamten Contraindicated
Frequently asked questions
Can I take Mavacamten with Norethisterone?
MediHelp rates the interaction as major. Mavacamten 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. Mavacamten may induce CYP3A4 and lower progestin exposure. This can cause contraceptive failure or breakthrough bleeding, and mavacamten is associated with fetal risk.
How serious is the interaction between Mavacamten 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 contraceptive method not affected by enzyme induction, such as an intrauterine system, or add condoms. Continue this for 4 months after the last mavacamten dose.
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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