Drug interactions
Fentanyl + Methocarbamol
Severity: Major
Fentanyl and Methocarbamol: major 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
Methocarbamol causes CNS depression, and combining it with fentanyl increases sedation, dizziness and the risk of respiratory depression. Opioid labeling cautions that concomitant CNS depressants can lead to profound sedation, respiratory depression, coma and death.
What this interaction means in plain words
Fentanyl and Methocarbamol can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for.
Fentanyl belongs to Musculoskeletal; Methocarbamol belongs to Musculoskeletal.
Why it happens
Additive central nervous system depression through pharmacodynamic synergy.
What to do
Use together only when alternatives are inadequate, with the lowest effective doses and shortest duration. Monitor for excessive sedation and slowed breathing and reduce the dose of either drug if these occur.
What to ask your pharmacist
- Does the benefit of taking both outweigh the risk in my case?
- Do I need any blood test, ECG or other check while on both?
- What early warning signs should I watch for, and what should I do if they appear?
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Other interactions of Fentanyl
- Alvimopan + Fentanyl Contraindicated
- Fentanyl + Isocarboxazid Contraindicated
- Fentanyl + Olanzapine / samidorphan Contraindicated
- Fentanyl + Phenelzine Contraindicated
- Fentanyl + Tranylcypromine Contraindicated
- Alfentanil + Fentanyl Major
Other interactions of Methocarbamol
Frequently asked questions
Can I take Fentanyl with Methocarbamol?
MediHelp rates the interaction as major. Fentanyl and Methocarbamol can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for. Methocarbamol causes CNS depression, and combining it with fentanyl increases sedation, dizziness and the risk of respiratory depression. Opioid labeling cautions that concomitant CNS depressants can lead to profound sedation, respiratory depression, coma and death.
How serious is the interaction between Fentanyl and Methocarbamol?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Use together only when alternatives are inadequate, with the lowest effective doses and shortest duration. Monitor for excessive sedation and slowed breathing and reduce the dose of either drug if these occur.
What other medicines interact with Fentanyl?
MediHelp also lists interactions of Fentanyl with, for example, Alvimopan, Isocarboxazid, Olanzapine / samidorphan. The full list is on the Fentanyl page.
Full monographs, dosing and an interaction checker in the MediHelp app
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