Drug interactions
Etonogestrel + Mavacamten
Severity: Major
Etonogestrel and Mavacamten: 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 reduce exposure to CYP3A4-metabolised hormonal contraceptives, risking contraceptive failure and breakthrough bleeding. This is important because mavacamten is not recommended in pregnancy.
What this interaction means in plain words
Etonogestrel and Mavacamten 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.
Etonogestrel belongs to Endocrine; Mavacamten belongs to Cardiovascular.
Why it happens
Mavacamten induces CYP3A4 and so may increase the metabolic clearance of etonogestrel.
What to do
Use a contraceptive method unaffected by enzyme induction, such as an IUD, or add barrier contraception during treatment and for several 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 Etonogestrel
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 Etonogestrel with Mavacamten?
MediHelp rates the interaction as major. Etonogestrel and Mavacamten 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 reduce exposure to CYP3A4-metabolised hormonal contraceptives, risking contraceptive failure and breakthrough bleeding. This is important because mavacamten is not recommended in pregnancy.
How serious is the interaction between Etonogestrel and Mavacamten?
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 unaffected by enzyme induction, such as an IUD, or add barrier contraception during treatment and for several months after the last mavacamten dose.
What other medicines interact with Etonogestrel?
MediHelp also lists interactions of Etonogestrel with, for example, Amobarbital, Armodafinil, Bosentan. The full list is on the Etonogestrel page.
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