Drug interactions
Chlorzoxazone + OnabotulinumtoxinA
Severity: Moderate
Chlorzoxazone and OnabotulinumtoxinA: 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
Systemic muscle relaxants might add to the neuromuscular weakness produced by botulinum toxin, especially if the toxin spreads beyond the injection site. The clinical evidence is limited and largely labeling-based.
What this interaction means in plain words
Chlorzoxazone and OnabotulinumtoxinA 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; OnabotulinumtoxinA belongs to Musculoskeletal.
Why it happens
Possible additive reduction of neuromuscular transmission and muscle tone.
What to do
Monitor for excessive weakness, swallowing or breathing difficulty after injection. Use the lowest effective toxin dose and consider holding the muscle relaxant if unexpected weakness appears.
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 OnabotulinumtoxinA
Frequently asked questions
Can I take Chlorzoxazone with OnabotulinumtoxinA?
MediHelp rates the interaction as moderate. Chlorzoxazone and OnabotulinumtoxinA 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. Systemic muscle relaxants might add to the neuromuscular weakness produced by botulinum toxin, especially if the toxin spreads beyond the injection site. The clinical evidence is limited and largely labeling-based.
How serious is the interaction between Chlorzoxazone and OnabotulinumtoxinA?
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 excessive weakness, swallowing or breathing difficulty after injection. Use the lowest effective toxin dose and consider holding the muscle relaxant if unexpected weakness appears.
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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