Drug interactions
Efavirenz + Metaxalone
Severity: Minor
Efavirenz and Metaxalone: minor 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 induces CYP3A4 and other enzymes and may lower metaxalone concentrations. Reduced muscle relaxant effect is possible, although the clinical effect is not well characterised.
What this interaction means in plain words
Efavirenz and Metaxalone have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised.
Efavirenz belongs to Anti Virals; Metaxalone belongs to Musculoskeletal.
Why it happens
Efavirenz induction of hepatic and intestinal CYP3A4 may increase metaxalone metabolism, which is partly CYP3A4-dependent.
What to do
Monitor for reduced muscle relaxant efficacy and adjust the metaxalone dose within the labelled range if needed. No empirical dose change is required at initiation.
What to ask your pharmacist
- Is there anything I should notice while taking both?
- Do I need to tell my doctor at the next visit?
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Other interactions of Metaxalone
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
Frequently asked questions
Can I take Efavirenz with Metaxalone?
MediHelp rates the interaction as minor. Efavirenz and Metaxalone have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised. Efavirenz induces CYP3A4 and other enzymes and may lower metaxalone concentrations. Reduced muscle relaxant effect is possible, although the clinical effect is not well characterised.
How serious is the interaction between Efavirenz and Metaxalone?
MediHelp rates it minor, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor for reduced muscle relaxant efficacy and adjust the metaxalone dose within the labelled range if needed. No empirical dose change is required at initiation.
What other medicines interact with Metaxalone?
MediHelp also lists interactions of Metaxalone with, for example, Alfentanil, Belladonna and opium, Benzhydrocodone / acetaminophen. The full list is on the Metaxalone page.
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