Acetaminophen And Codeine and Schisandra Sphenanthera: 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
Schisandra Sphenanthera
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.
Your pain medicine contains codeine, which your body turns into morphine to relieve pain. The herbal supplement Schisandra can slow down one of the liver enzymes (CYP3A4) that helps break codeine down. When that happens, more codeine and morphine can build up in your body than expected.
That extra buildup could make side effects stronger, like heavy drowsiness or slowed, shallow breathing, which can be dangerous. This warning is based on theory rather than proven cases, so please don't panic. Don't stop either one on your own. Just let your pharmacist or doctor know you take both so they can watch you closely and adjust things if needed.
Effect: Increased codeine and morphine exposure via inhibition of CYP3A4-mediated codeine metabolism by Schisandra sphenanthera.
Direction: Codeine's parent-drug accumulation increases available substrate; the concern is elevated opioid exposure and enhanced/prolonged opioid effects, including potentially fatal respiratory depression.
- Evidence: Theoretical.
- Onset: Unspecified.
- Severity: Major.
- Management: If used together, monitor for sedation and respiratory depression; consider reducing codeine dose until stable effect is seen. Risk is highest when the inhibitor is added to a stable codeine regimen. On inhibitor discontinuation, watch for opioid withdrawal and consider dose increase.
What happens
Increased codeine and morphine exposure
Interaction Deep Dive
Taking codeine together with CYP3A4 inhibitors has led to higher levels of both codeine and morphine, which may intensify or extend adverse effects and could produce respiratory depression that is potentially fatal, especially in cases where an inhibitor is introduced once a patient has already been stabilized on a codeine dose. When such combined use cannot be avoided, watch patients carefully for sedation and respiratory depression, and think about lowering the codeine dose until the drug's effects are seen to be stable. Conversely, when a CYP3A4 inhibitor is being withdrawn, observe patients for indications of opioid withdrawal, and consider raising the codeine dose until stable drug effects have been observed12.
Why it happens (mechanism)
Inhibition of CYP3A4-mediated codeine metabolism
How to manage this interaction
Keep taking both as prescribed unless your care team tells you otherwise. This is a manageable interaction.
- Tell your pharmacist and prescriber you use Schisandra with your codeine product.
- Your codeine dose may need to be adjusted and individualized by your care team, and they may monitor you more closely for excessive sleepiness or slowed breathing.
- Watch especially in the first days after adding the supplement to a steady codeine dose.
- If you stop the Schisandra, tell your team, since they may need to review your codeine dose and watch for withdrawal signs.
Management is individual — confirm any change with your pharmacist or prescriber.
Common questions
Can I take Acetaminophen And Codeine and Schisandra Sphenanthera together?
Schisandra may slow how you break down codeine, raising codeine and morphine levels and the risk of heavy sedation or slowed breathing. Keep taking both as prescribed and tell your pharmacist or doctor so they can monitor you and adjust the dose. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Acetaminophen And Codeine and Schisandra Sphenanthera 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 Schisandra Sphenanthera interaction managed?
Keep taking both as prescribed unless your care team tells you otherwise. This is a manageable interaction. Tell your pharmacist and prescriber you use Schisandra with your codeine product. Your codeine dose may need to be adjusted and individualized by your care team, and they may monitor you more closely for excessive sleepiness or slowed breathing. Watch especially in the first days after addin… 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 Schisandra Sphenanthera 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
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