Drug interactions
Metaxalone + Phenobarbital
Severity: Moderate
Metaxalone and Phenobarbital: moderate 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
Phenobarbital is a long-acting sedative, and combining it with metaxalone can cause excess drowsiness and impaired alertness. Phenobarbital is also a CYP3A4 inducer and may lower metaxalone exposure over time.
What this interaction means in plain words
Metaxalone and Phenobarbital can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken.
Why it happens
Additive CNS depression plus induction of hepatic enzymes by phenobarbital.
What to do
Monitor for oversedation and for reduced muscle-relaxant effect. Adjust the metaxalone dose according to response and warn the patient about driving.
What to ask your pharmacist
- Should I take them at different times of day?
- Does the dose of either medicine need to change?
- Is there anything I should avoid, such as alcohol or certain foods, while on both?
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Other interactions of Metaxalone
Frequently asked questions
Can I take Metaxalone with Phenobarbital?
MediHelp rates the interaction as moderate. Metaxalone and Phenobarbital can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken. Phenobarbital is a long-acting sedative, and combining it with metaxalone can cause excess drowsiness and impaired alertness. Phenobarbital is also a CYP3A4 inducer and may lower metaxalone exposure over time.
How serious is the interaction between Metaxalone and Phenobarbital?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor for oversedation and for reduced muscle-relaxant effect. Adjust the metaxalone dose according to response and warn the patient about driving.
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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