Drug interactions
Chlorzoxazone + Primidone
Severity: Moderate
Chlorzoxazone and Primidone: 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
Primidone is metabolized to phenobarbital and is sedating, so chlorzoxazone may add to drowsiness and impaired coordination. Enzyme induction by primidone may also reduce chlorzoxazone exposure.
What this interaction means in plain words
Chlorzoxazone and Primidone 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.
Chlorzoxazone belongs to Musculoskeletal; Primidone belongs to Central Nervous System.
Why it happens
Additive central nervous system depression; primidone-derived enzyme induction may increase chlorzoxazone clearance.
What to do
Monitor for excess sedation and use the lowest effective doses. Review muscle relaxant efficacy, as it may be reduced.
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 Chlorzoxazone
Other interactions of Primidone
- Lorlatinib + Primidone Contraindicated
- Lurasidone + Primidone Contraindicated
- Primidone + Ranolazine Contraindicated
- Primidone + Sofosbuvir-velpatasvir-voxilaprevir Contraindicated
- Primidone + Voriconazole Contraindicated
- Abiraterone + Primidone Major
Frequently asked questions
Can I take Chlorzoxazone with Primidone?
MediHelp rates the interaction as moderate. Chlorzoxazone and Primidone 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. Primidone is metabolized to phenobarbital and is sedating, so chlorzoxazone may add to drowsiness and impaired coordination. Enzyme induction by primidone may also reduce chlorzoxazone exposure.
How serious is the interaction between Chlorzoxazone and Primidone?
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 excess sedation and use the lowest effective doses. Review muscle relaxant efficacy, as it may be reduced.
What other medicines interact with Chlorzoxazone?
MediHelp also lists interactions of Chlorzoxazone with, for example, Alfentanil, Alprazolam, Amobarbital. The full list is on the Chlorzoxazone page.
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