Acetaminophen And Codeine and Eliglustat: 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
Eliglustat
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 pill contains codeine, which is a bit unusual. Codeine doesn't work by itself. Your body has to change it into morphine, and that morphine is what actually relieves your pain. It uses a liver enzyme called CYP2D6 to do this.
Eliglustat (Cerdelga) slows that enzyme down. So less codeine gets turned into morphine, which means your codeine may not relieve pain as well. This is still a possible (theoretical) concern, not something proven, so don't worry. Keep taking both as prescribed and let your pharmacist or doctor know if your pain isn't controlled. They can manage this easily.
Mechanism: Eliglustat inhibits CYP2D6, the enzyme that O-demethylates codeine (a prodrug) to its active metabolite morphine.
- Direction: Increased parent codeine exposure, reduced morphine formation, so reduced analgesic efficacy and possible opioid withdrawal.
- Evidence: Theoretical; magnitude not quantified.
- Onset: Unspecified.
- Management: If co-use is necessary, monitor for inadequate analgesia and withdrawal; the codeine dose may be increased and individualized by the care team. When eliglustat is stopped, CYP2D6 activity recovers, so the codeine dose may need reduction with monitoring for sedation and respiratory depression.
What happens
Increased codeine exposure and reduced active metabolite (morphine) exposure
Interaction Deep Dive
Concomitant use of codeine and a CYP2D6 inhibitor may reduce plasma concentrations of morphine, the active metabolite of codeine, thus potentially leading to reduced efficacy and withdrawal symptoms. If concomitant use is necessary, monitor patients for withdrawal symptoms and consider increasing the codeine dose. Once the CYP2D6 inhibitor is discontinued, consider reducing the codeine dose and monitor for signs and symptoms of respiratory depression and sedation312.
Why it happens (mechanism)
Inhibition of CYP2D6-mediated codeine metabolism
How to manage this interaction
Good news is your care team can handle this by tailoring your dose and watching how you respond.
- Keep taking both exactly as prescribed unless told otherwise.
- Tell your prescriber if your pain is not well controlled or you feel withdrawal-type symptoms. Your codeine dose may be adjusted and individualized for you.
- If eliglustat is ever stopped, mention it, because your codeine dose may need to be lowered and you may be watched more closely for excess drowsiness or slowed breathing.
- Raise any questions 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 Eliglustat together?
Eliglustat can blunt how well codeine relieves pain by blocking its conversion to morphine, so tell your care team if your pain isn't controlled; they can adjust the dose and monitor you. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Acetaminophen And Codeine and Eliglustat 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 Eliglustat interaction managed?
Good news is your care team can handle this by tailoring your dose and watching how you respond. Keep taking both exactly as prescribed unless told otherwise. Tell your prescriber if your pain is not well controlled or you feel withdrawal-type symptoms. Your codeine dose may be adjusted and individualized for you. If eliglustat is ever stopped, mention it, because your codeine dose may need to be… 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 Eliglustat 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 (3)
- 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
- Product Information: codeine sulfate oral tablets, codeine sulfate oral tablets. West-Ward Pharmaceuticals Corp. (per FDA), Eatontown, NJ, 2017. DailyMed
Keep reading about Acetaminophen And Codeine
Keep reading about Eliglustat
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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