Drug interactions
Butorphanol + Fentanyl
Severity: Major
Butorphanol and Fentanyl: major interaction.
Last updated Sources: US FDA label
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
Butorphanol, a mixed agonist-antagonist, can partially block fentanyl's mu-receptor effects, reducing analgesia and possibly precipitating withdrawal in opioid-dependent patients. Both are also opioid CNS depressants, so respiratory depression and sedation can add up.
What this interaction means in plain words
Butorphanol and Fentanyl 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.
Butorphanol belongs to Musculoskeletal; Fentanyl belongs to Musculoskeletal.
Why it happens
Kappa agonism with mu partial antagonism opposes fentanyl, while additive opioid CNS depression also occurs.
What to do
Avoid combining; select one opioid regimen. If switching, monitor for withdrawal, loss of analgesia and respiratory depression.
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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References
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 Butorphanol
- Butorphanol + Olanzapine / samidorphan Contraindicated
- Butorphanol + Sodium oxybate Contraindicated
- Alfentanil + Butorphanol Major
- Alprazolam + Butorphanol Major
- Alvimopan + Butorphanol Major
- Amobarbital + Butorphanol Major
Frequently asked questions
Can I take Butorphanol with Fentanyl?
MediHelp rates the interaction as major. Butorphanol and Fentanyl 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. Butorphanol, a mixed agonist-antagonist, can partially block fentanyl's mu-receptor effects, reducing analgesia and possibly precipitating withdrawal in opioid-dependent patients. Both are also opioid CNS depressants, so respiratory depression and sedation can add up.
How serious is the interaction between Butorphanol and Fentanyl?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid combining; select one opioid regimen. If switching, monitor for withdrawal, loss of analgesia and respiratory depression.
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.
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