Codeine and Buprenorphine: Interaction Details
AI-assisted, pharmacist-reviewed · AI content regenerated Jul 11, 2026 · Source data updated Jul 2, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Buprenorphine
Codeine
How we grade severity & evidence
Severity levels
- Contraindicated: These should generally not be used together.
- Major: Potentially serious — often needs a change or close monitoring.
- Moderate: Can be significant — usually manageable with monitoring.
- Minor: Usually limited clinical impact.
Evidence grades
- Established: Well documented — supported by controlled studies or strong clinical data.
- Probable: Good supporting evidence, though not definitively proven.
- Suspected: Some evidence suggests this interaction, but it is not well established.
- Possible: Limited or conflicting evidence; the interaction may occur.
- Theoretical: Predicted from the drugs' pharmacology; not yet confirmed in people.
Ratings come from the documented interaction literature and are reviewed by a pharmacist. They describe the documented risk of the combination, not what will necessarily happen to you — your dose, timing, and health picture all matter.
Buprenorphine and codeine can work against each other and also stack up risky side effects. Buprenorphine grabs onto the same pain receptors that codeine needs, and it holds on very tightly. Because of that, it can block codeine from working, so your pain relief may drop. In someone who is used to opioids, buprenorphine can even trigger sudden withdrawal (sweating, cramps, aches, feeling sick).
At the same time, both are central nervous system depressants, so together they can cause too much sleepiness, slowed breathing, low blood pressure, or in serious cases coma. There is also a chance of serotonin syndrome. This is a real safety concern, but your doctor and pharmacist can manage it. Please talk with them before taking both.
Direction/mechanism: Buprenorphine is a high-affinity partial mu-opioid agonist/antagonist. At the receptor it competitively displaces or blocks full agonists, so codeine's active metabolite (morphine, formed via CYP2D6, since codeine is a prodrug) has reduced analgesic effect and can precipitate withdrawal in opioid-dependent patients. Superimposed on this are additive CNS depression (respiratory depression, hypotension, sedation, coma, death) and additive serotonergic risk.
- Severity: major; evidence: theoretical; onset: unspecified.
- Management: avoid combination; reserve for inadequate alternatives, use minimum dose/duration, monitor closely for sedation/respiratory depression especially at initiation and titration, consider naloxone, and discontinue codeine if serotonin syndrome is suspected.
What happens
Reduced analgesic effect and/or precipitation of withdrawal symptoms, an increased risk of serotonin syndrome and an increased risk of hypotension, respiratory depression, profound sedation, coma, and death
Interaction Deep Dive
Do not combine codeine with buprenorphine (a serotonergic CNS depressant that acts as a mixed opioid agonist/antagonist or a partial agonist opioid analgesic), because this combination can diminish codeine's analgesic effect and trigger withdrawal symptoms, raise the likelihood of serotonin syndrome, and heighten the risk of hypotension, respiratory depression, profound sedation, coma, and death. Prescribing both agents together should be limited to patients whose alternative treatment options are inadequate. Keep doses and treatment durations as low and as short as possible. Monitor patients closely for indications of respiratory depression and sedation. When concurrent use is justified, observe the patient carefully, especially when starting therapy and when adjusting the dose. Stop codeine if serotonin syndrome is suspected, and consider prescribing naloxone as emergency treatment for opioid overdose1.
Why it happens (mechanism)
Competitive binding at opioid receptors; additive serotonergic effects; additive CNS depression
How to manage this interaction
Do not start or stop either drug on your own. Care teams generally avoid using codeine and buprenorphine together and reserve the combination only when other options are not enough.
- Keep taking both exactly as prescribed unless your prescriber tells you otherwise.
- Expect your team to use the lowest dose for the shortest time needed, and to watch you closely, especially when starting or adjusting doses.
- Your team may prescribe naloxone as an emergency backup.
- Get urgent help for very slow or shallow breathing, severe drowsiness, or fainting.
- Report agitation, fast heartbeat, sweating, tremor, or fever (possible serotonin syndrome).
Ask your pharmacist or prescriber before combining these.
Management is individual — confirm any change with your pharmacist or prescriber.
Common questions
Can I take Codeine and Buprenorphine together?
Buprenorphine can block codeine's pain relief and trigger withdrawal, and combining them adds up dangerous sedation and breathing risks, so this pairing is generally avoided. Do not change either medicine on your own; talk with your pharmacist or prescriber first. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Codeine and Buprenorphine interaction?
It is rated major. Potentially serious — often needs a change or close monitoring.
How quickly could this interaction happen?
The documented onset is "unspecified". The timing of this interaction is not well characterized.
How is the Codeine and Buprenorphine interaction managed?
Do not start or stop either drug on your own. Care teams generally avoid using codeine and buprenorphine together and reserve the combination only when other options are not enough. Keep taking both exactly as prescribed unless your prescriber tells you otherwise. Expect your team to use the lowest dose for the shortest time needed, and to watch you closely, especially when starting or adjusting d… Management is individual — always follow your own care team's guidance.
How strong is the evidence for this interaction?
The evidence is graded "theoretical". Predicted from the drugs' pharmacology; not yet confirmed in people.
From our Q&A
Real reader questions about these medications, each personally answered by our pharmacist:
Questions for your pharmacist
- Does my dose of Codeine or Buprenorphine need adjusting while I take them together?
- What symptoms should prompt me to call you or my prescriber right away?
- Does the timing of my doses matter for this combination?
- Is there a safer alternative to one of these medications for me?
References (1)
- Product Information: CARISOPRODOL, ASPIRIN, CODEINE PHOSPHATE oral tablets, carisoprodol, aspirin, codeine phosphate oral tablets. Ingenus Pharmaceuticals LLC (per DailyMed), Orlando, FL, 2021. DailyMed
Keep reading about Buprenorphine
Keep reading about Codeine
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Prescription drugs aren't the whole picture — herbal and dietary supplements can interact with them too. From the evidence-graded Natural Medicines database:
major · moderate · minor — check everything you take with our drug–supplement interaction checker.
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