Drug interactions
Butorphanol + Phenobarbital
Severity: Major
Butorphanol and Phenobarbital: 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
Phenobarbital combined with butorphanol can cause deep sedation, respiratory depression, coma, and death. The risk is greatest at higher doses and in frail or respiratory-compromised patients.
What this interaction means in plain words
Butorphanol and Phenobarbital 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.
Why it happens
Additive CNS and respiratory depression through opioid receptor agonism and enhanced GABA-A activity.
What to do
Avoid combination where possible; if needed, use the lowest effective doses and titrate carefully. Monitor respiratory rate and consciousness closely.
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?
Pro+ members
Unlock the full page
Create an account and start a Pro+ trial to unlock the full management advice for Butorphanol and Phenobarbital, the additional notes, the evidence detail and the whole-prescription interaction checker.
- Full clinical management advice
- Additional notes
- Evidence detail
- Interaction checker for a whole prescription
Try Pro+ free for 7 days on the web. No card needed.
References
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 Phenobarbital?
MediHelp rates the interaction as major. Butorphanol and Phenobarbital 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. Phenobarbital combined with butorphanol can cause deep sedation, respiratory depression, coma, and death. The risk is greatest at higher doses and in frail or respiratory-compromised patients.
How serious is the interaction between Butorphanol and Phenobarbital?
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 combination where possible; if needed, use the lowest effective doses and titrate carefully. Monitor respiratory rate and consciousness closely.
What other medicines interact with Butorphanol?
MediHelp also lists interactions of Butorphanol with, for example, Olanzapine / samidorphan, Sodium oxybate, Alfentanil. The full list is on the Butorphanol page.
Full monographs, dosing and an interaction checker in the MediHelp app
Open the complete reference, check multi-drug interactions and use dosing tools in the MediHelp app.
