Mavorixafor and Acetaminophen And Codeine: 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
Mavorixafor
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 medicines don't mix well. Codeine is a "prodrug," which means your body has to switch it on using an enzyme called CYP2D6 before it can relieve pain. Mavorixafor (Xolremdi) blocks that same enzyme.
Because of this, codeine can behave unpredictably. Some of it may build up as morphine while it is being processed, which raises the chance of side effects like heavy drowsiness, slowed breathing, constipation, or nausea. The acetaminophen part is not the concern here. This combination is one that experts say should be avoided, so please talk with your pharmacist or doctor before taking them together. Your care team can help you find a safer option.
Contraindicated combination. Mavorixafor is a CYP2D6 inhibitor. Codeine depends on CYP2D6 for conversion to morphine, its active metabolite, so inhibition alters its PK/PD unpredictably and increases exposure to CYP2D6-handled substrate/metabolites, raising opioid-related adverse event risk (sedation, respiratory depression).
- Mechanism: inhibition of CYP2D6-mediated metabolism.
- Magnitude: with dextromethorphan, mavorixafor 400 mg gave ~6-fold Cmax and ~9-fold AUC increases.
- Evidence: probable; onset unspecified.
- Management: avoid concurrent use; select a non-CYP2D6-dependent analgesic. Acetaminophen component is not implicated.
What happens
Increased CYP2D6 substrate exposure and an increased risk of CYP2D6 substrate-related adverse events
Interaction Deep Dive
Using mavorixafor (a CYP2D6 inhibitor) together with medications that rely heavily on CYP2D6 for their clearance is contraindicated. When mavorixafor is given alongside CYP2D6 substrates, exposure to those substrates may rise, potentially raising the likelihood of adverse reactions linked to CYP2D6. A drug interaction study in healthy subjects showed that combining mavorixafor 400 mg with the CYP2D6 substrate dextromethorphan produced increases of 6-fold in Cmax and 9-fold in AUC1.
Why it happens (mechanism)
Inhibition of CYP2D6-mediated metabolism by mavorixafor
How to manage this interaction
Keep taking your medicines exactly as prescribed and do not stop either one on your own. This pairing is flagged as one to avoid, so raise it with your prescriber or pharmacist promptly.
- Your care team will likely choose a different pain medicine that does not rely on the CYP2D6 enzyme instead of the codeine product.
- Ask which analgesic is safe to use with mavorixafor.
- Report any strong drowsiness, slow or shallow breathing, confusion, or severe constipation right away.
Your team can manage this safely by selecting an alternative and tailoring your care.
Management is individual — confirm any change with your pharmacist or prescriber.
Literature reports
1 report — tap to read
a) In a study evaluating drug interactions, giving mavorixafor (a CYP2D6 inhibitor) 400 mg together with dextromethorphan (a CYP2D6 substrate) in healthy subjects produced a 6-fold rise in Cmax and a 9-fold rise in AUC, respectively 1.
Common questions
Can I take Mavorixafor and Acetaminophen And Codeine together?
Codeine relies on the CYP2D6 enzyme that mavorixafor blocks, making its effects unpredictable and raising the risk of opioid side effects, so this combination should be avoided. Talk to your doctor or pharmacist about a different pain medicine. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Mavorixafor and Acetaminophen And Codeine interaction?
It is rated contraindicated. These should generally not be used together.
How quickly could this interaction happen?
The documented onset is "unspecified". The timing of this interaction is not well characterized.
How is the Mavorixafor and Acetaminophen And Codeine interaction managed?
Keep taking your medicines exactly as prescribed and do not stop either one on your own. This pairing is flagged as one to avoid, so raise it with your prescriber or pharmacist promptly. Your care team will likely choose a different pain medicine that does not rely on the CYP2D6 enzyme instead of the codeine product. Ask which analgesic is safe to use with mavorixafor. Report any strong drowsiness… Management is individual — always follow your own care team's guidance.
How strong is the evidence for this interaction?
The evidence is graded "probable". Good supporting evidence, though not definitively proven.
Questions for your pharmacist
- Does my dose of Mavorixafor or Acetaminophen And Codeine 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: XOLREMDI(TM) oral capsules, mavorixafor oral capsules. X4 Pharmaceuticals, Inc. (Per FDA), Boston, MA, 2024. DailyMed
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