Acetaminophen And Codeine and Mavacamten: Interaction Details
AI-assisted, pharmacist-reviewed · AI content regenerated Jul 11, 2026 · Source data updated Jul 1, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Acetaminophen And Codeine
Mavacamten
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.
Your pain medicine contains codeine, which your body has to switch on before it can relieve pain. Mavacamten (Camzyos) can speed up the liver enzyme that handles codeine, so you may end up with less active pain relief, not more. If you take codeine regularly, you could even notice early withdrawal feelings like aches, chills, sweating, or an upset stomach.
The good news is this is manageable. Keep taking both medicines as prescribed and let your pharmacist or doctor know if your pain is not as well controlled or you feel out of sorts. Your care team can adjust and personalize your dose and watch you more closely.
Effect: Mavacamten is a CYP3A4 inducer; codeine is a prodrug requiring bioactivation. Induction shunts codeine toward norcodeine, lowering codeine exposure and reducing CYP2D6-mediated conversion to morphine.
Direction: Reduced opioid efficacy; possible withdrawal in physically dependent patients.
- Evidence: Theoretical.
- Onset: Unspecified.
- Severity: Major.
- Management: Monitor for decreased analgesia and withdrawal signs; codeine dose may need to be increased and individualized. If mavacamten is later discontinued, anticipate rising opioid effect, consider dose reduction, and monitor for sedation and respiratory depression.
What happens
Reduced codeine and morphine exposure, reduced opioid efficacy and precipitation of opioid withdrawal
Interaction Deep Dive
When codeine is taken alongside CYP3A4 inducers, codeine concentrations may fall while norcodeine concentrations rise, and CYP2D6-mediated metabolism may decline, yielding lower morphine levels; this can diminish effectiveness or trigger a withdrawal syndrome in patients who have become physically dependent. Where combined use cannot be avoided, watch patients carefully for reduced efficacy or indications of opioid withdrawal syndrome, and consider raising the codeine dose if needed. Should a CYP3A4 inducer be withdrawn, consider lowering the codeine dose and monitor patients closely for evidence of respiratory depression or sedation12.
Why it happens (mechanism)
Induction of CYP3A4-mediated codeine metabolism
How to manage this interaction
Keep taking both medicines as prescribed unless your prescriber tells you otherwise.
- Watch for less pain relief or signs of opioid withdrawal (aches, sweating, chills, nausea, restlessness), and report these to your care team.
- Your team may monitor you more closely and may adjust and individualize your codeine dose as needed.
- If mavacamten is ever stopped, tell your prescriber, because your codeine may then feel stronger and your dose may need lowering to avoid excess sedation or slowed breathing.
Bring up any changes in pain control with your pharmacist or doctor.
Management is individual — confirm any change with your pharmacist or prescriber.
Common questions
Can I take Acetaminophen And Codeine and Mavacamten together?
Mavacamten may speed up how your body clears codeine, weakening its pain relief and possibly triggering withdrawal; keep taking both as prescribed and tell your care team if your pain is undertreated or you feel withdrawal symptoms. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Acetaminophen And Codeine and Mavacamten 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 Mavacamten interaction managed?
Keep taking both medicines as prescribed unless your prescriber tells you otherwise. Watch for less pain relief or signs of opioid withdrawal (aches, sweating, chills, nausea, restlessness), and report these to your care team. Your team may monitor you more closely and may adjust and individualize your codeine dose as needed. If mavacamten is ever stopped, tell your prescriber, because your codein… 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 Mavacamten 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 (2)
- Product Information: Codeine sulfate oral solution, codeine sulfate oral solution. Hikma Pharmaceuticals USA Inc(per FDA), Berkeley Heights, NJ, 2023. DailyMed
- Product Information: Codeine sulfate oral tablets, codeine sulfate oral tablets. Hikma Pharmaceuticals USA Inc. (per FDA), Berkeley Heights, NJ, 2023. DailyMed
Keep reading about Acetaminophen And Codeine
Keep reading about Mavacamten
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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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