Drug interactions
Efavirenz + Mavacamten
Severity: Contraindicated
Efavirenz and Mavacamten: contraindicated 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
Efavirenz affects CYP2C19 and CYP3A4, both of which metabolise mavacamten, so exposure may become unpredictable. Increased exposure can cause systolic dysfunction and heart failure, while reduced exposure impairs efficacy.
What this interaction means in plain words
Efavirenz and Mavacamten are not normally used together. Taking them at the same time is expected to cause harm or make one of them unsafe, so a different medicine is usually chosen for one of the two.
Efavirenz belongs to Anti Virals; Mavacamten belongs to Cardiovascular.
Why it happens
Efavirenz modulation of CYP3A4 and CYP2C19 metabolism of mavacamten.
What to do
Avoid the combination and use an alternative antiretroviral. If an interacting drug is started or stopped, monitor LVEF closely.
What to ask your pharmacist
- Is there an alternative to one of these two medicines for me?
- If both are essential, who is monitoring me and how often?
- Which symptoms mean I should stop and seek help straight away?
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Other interactions of Efavirenz
- Cobimetinib + Efavirenz Contraindicated
- Dienogest / estradiol valerate + Efavirenz Contraindicated
- Dihydroergotamine intranasal + Efavirenz Contraindicated
- Dihydroergotamine + Efavirenz Contraindicated
- Doravirine + Efavirenz Contraindicated
- Efavirenz + Elbasvir / grazoprevir Contraindicated
Other interactions of Mavacamten
- Apalutamide + Mavacamten Contraindicated
- Carbamazepine + Mavacamten Contraindicated
- Clarithromycin + Mavacamten Contraindicated
- Dexlansoprazole + Mavacamten Contraindicated
- Enzalutamide + Mavacamten Contraindicated
- Eslicarbazepine + Mavacamten Contraindicated
Frequently asked questions
Can I take Efavirenz with Mavacamten?
MediHelp rates the interaction as contraindicated. Efavirenz and Mavacamten are not normally used together. Taking them at the same time is expected to cause harm or make one of them unsafe, so a different medicine is usually chosen for one of the two. Efavirenz affects CYP2C19 and CYP3A4, both of which metabolise mavacamten, so exposure may become unpredictable. Increased exposure can cause systolic dysfunction and heart failure, while reduced exposure impairs efficacy.
How serious is the interaction between Efavirenz and Mavacamten?
MediHelp rates it contraindicated, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid the combination and use an alternative antiretroviral. If an interacting drug is started or stopped, monitor LVEF closely.
What other medicines interact with Efavirenz?
MediHelp also lists interactions of Efavirenz with, for example, Cobimetinib, Dienogest / estradiol valerate, Dihydroergotamine intranasal. The full list is on the Efavirenz page.
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