Drug interactions
Phenobarbital + Tizanidine
Severity: Moderate
Phenobarbital and Tizanidine: 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 an enzyme inducer that may lower tizanidine concentrations and reduce its effect. It also adds CNS depression, so both reduced efficacy and increased sedation are possible.
What this interaction means in plain words
Phenobarbital and Tizanidine 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
Induction of hepatic metabolism, including CYP1A2, lowers tizanidine exposure, with additive sedation.
What to do
Monitor spasticity control and titrate tizanidine to effect. Watch for sedation and hypotension.
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 Tizanidine
- Ciprofloxacin + Tizanidine Contraindicated
- Fluvoxamine + Tizanidine Contraindicated
- Pefloxacin + Tizanidine Contraindicated
- Pipemidic acid + Tizanidine Contraindicated
- Benzhydrocodone / acetaminophen + Tizanidine Major
- Brexanolone + Tizanidine Major
Frequently asked questions
Can I take Phenobarbital with Tizanidine?
MediHelp rates the interaction as moderate. Phenobarbital and Tizanidine 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 an enzyme inducer that may lower tizanidine concentrations and reduce its effect. It also adds CNS depression, so both reduced efficacy and increased sedation are possible.
How serious is the interaction between Phenobarbital and Tizanidine?
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 spasticity control and titrate tizanidine to effect. Watch for sedation and hypotension.
What other medicines interact with Tizanidine?
MediHelp also lists interactions of Tizanidine with, for example, Ciprofloxacin, Fluvoxamine, Pefloxacin. The full list is on the Tizanidine page.
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