Drug interactions
Butorphanol + Primidone
Severity: Major
Butorphanol and Primidone: major interaction.
Last updated Sources: Health Canada product monograph
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
Primidone is metabolised to phenobarbital and has sedative effects. With butorphanol, the risk of excessive sedation and respiratory depression is increased.
What this interaction means in plain words
Butorphanol and Primidone 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; Primidone belongs to Central Nervous System.
Why it happens
Additive CNS and respiratory depression via opioid agonism and barbiturate (phenobarbital-mediated) GABA-A enhancement.
What to do
Use the lowest effective opioid dose and monitor sedation and respiratory status. Counsel patients to avoid alcohol and driving.
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 Butorphanol
- Butorphanol + Olanzapine / samidorphan Contraindicated
- Butorphanol + Sodium oxybate Contraindicated
- Alfentanil + Butorphanol Major
- Alprazolam + Butorphanol Major
- Alvimopan + Butorphanol Major
- Amobarbital + Butorphanol Major
Other interactions of Primidone
- Lorlatinib + Primidone Contraindicated
- Lurasidone + Primidone Contraindicated
- Primidone + Ranolazine Contraindicated
- Primidone + Sofosbuvir-velpatasvir-voxilaprevir Contraindicated
- Primidone + Voriconazole Contraindicated
- Abiraterone + Primidone Major
Frequently asked questions
Can I take Butorphanol with Primidone?
MediHelp rates the interaction as major. Butorphanol and Primidone 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. Primidone is metabolised to phenobarbital and has sedative effects. With butorphanol, the risk of excessive sedation and respiratory depression is increased.
How serious is the interaction between Butorphanol and Primidone?
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 the lowest effective opioid dose and monitor sedation and respiratory status. Counsel patients to avoid alcohol and driving.
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.
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