Acetaminophen And Codeine and Nalbuphine: Interaction Details
AI-assisted, pharmacist-reviewed · AI content regenerated Jul 11, 2026 · Source data updated Jun 30, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Acetaminophen And Codeine
Nalbuphine
No brand names on record
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.
These two pain medicines can work against each other and also add up in risky ways. Your Tylenol with codeine is a regular opioid. Nalbuphine is a different kind of opioid that can actually block some of codeine's pain relief. So you might get less relief, and if your body is used to codeine, nalbuphine can even trigger sudden withdrawal (chills, cramps, sweating, feeling awful).
At the same time, both can slow your breathing and make you very drowsy, which together can be dangerous. Please don't change anything on your own. Talk with your pharmacist or doctor, who can pick a safer plan and watch you closely.
Direction: Nalbuphine (mixed opioid agonist/antagonist) competes with codeine at opioid receptors, potentially reducing analgesia and precipitating withdrawal in opioid-dependent patients. Additive CNS/respiratory depression and additive serotonergic effects raise risk of profound sedation, hypotension, respiratory depression, serotonin syndrome, and death.
- Mechanism: competitive receptor binding plus additive CNS depression and serotonergic activity.
- Evidence: theoretical; severity major; onset unspecified.
- Management: avoid combination; reserve for when alternatives are inadequate. Use minimum dose/duration, monitor for sedation and respiratory depression especially at initiation/titration. Discontinue codeine if serotonin syndrome suspected; consider naloxone availability.
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 use codeine together with nalbuphine, which acts as a serotonergic CNS depressant and functions as either a mixed opioid agonist/antagonist or a partial opioid agonist analgesic. Combining them 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 concurrently should be limited to patients whose other treatment choices are insufficient. Keep doses and treatment length to the lowest amount needed, and monitor patients closely for indications of respiratory depression and sedation. When their combined use is justified, observe the patient carefully, especially when starting therapy and modifying the dose. Stop codeine if serotonin syndrome is suspected, and consider prescribing naloxone for emergency management of opioid overdose1.
Why it happens (mechanism)
Competitive binding at opioid receptors; additive serotonergic effects; additive CNS depression
How to manage this interaction
The main advice is to avoid using these two together when possible. Your care team may choose one opioid rather than combining them, since nalbuphine can blunt codeine's pain relief and even trigger withdrawal.
- Keep taking what you were prescribed, and don't stop or add anything on your own.
- If both are truly needed, your team will use the lowest dose for the shortest time and monitor you closely, especially at the start or when doses change.
- Get help right away for very slow or shallow breathing, extreme drowsiness, confusion, fever, agitation, or shakiness.
- Ask your pharmacist or prescriber whether naloxone should be on hand.
Management is individual — confirm any change with your pharmacist or prescriber.
Common questions
Can I take Acetaminophen And Codeine and Nalbuphine together?
Combining codeine with nalbuphine can reduce pain relief, trigger withdrawal, and dangerously add to sedation and slowed breathing, so this pairing is best avoided. Let your pharmacist or doctor choose one opioid and monitor you. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Acetaminophen And Codeine and Nalbuphine 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 Acetaminophen And Codeine and Nalbuphine interaction managed?
The main advice is to avoid using these two together when possible. Your care team may choose one opioid rather than combining them, since nalbuphine can blunt codeine's pain relief and even trigger withdrawal. Keep taking what you were prescribed, and don't stop or add anything on your own. If both are truly needed, your team will use the lowest dose for the shortest time and monitor you closely,… 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.
Questions for your pharmacist
- Does my dose of Acetaminophen And Codeine or Nalbuphine 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 Acetaminophen And Codeine
Keep reading about Nalbuphine
These medications also interact with supplements
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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