Acetaminophen And Codeine and Busulfan: 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
Busulfan
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 here is a combination of acetaminophen (Tylenol) plus codeine. The part that matters for this interaction is the acetaminophen. Busulfan is a chemotherapy medicine that your body clears using a natural helper called glutathione. Acetaminophen can lower glutathione levels, so taking it right before or during busulfan might slow how fast busulfan leaves your body, meaning a bit more could build up.
Here is the reassuring part: this concern is theoretical, and the real-world importance is not yet known. Your cancer care team knows about timing like this and can plan around it. Please don't change anything on your own, just let your team know you take this medicine so they can guide you.
Effect: Possible reduced busulfan clearance. The acetaminophen component (not codeine) is the culprit.
Mechanism: Acetaminophen depletes glutathione, and busulfan is eliminated via glutathione conjugation. Reduced substrate availability may decrease busulfan clearance and raise exposure (AUC). Onset is delayed.
Evidence: Theoretical; clinical significance undefined.
- Avoid or minimize acetaminophen within 72 hours before and during busulfan administration.
- Busulfan is narrow-therapeutic-index; consider PK monitoring per institutional protocol if concomitant use is unavoidable.
- Dose may be individualized by the transplant/oncology team.
What happens
Reduced busulfan clearance
Interaction Deep Dive
Acetaminophen decreases glutathione levels in the blood and tissues, and busulfan is eliminated from the body via conjugation with glutathione. Therefore, use of acetaminophen less than 72 hours before or concurrently with busulfan may result in reduced busulfan clearance1. The clinical significance of this interaction is not yet known.
Why it happens (mechanism)
Decreased glutathione available for conjugation
How to manage this interaction
Keep taking both exactly as prescribed and let your oncology or transplant team know you use this acetaminophen-codeine product.
- The main step is timing: teams typically try to minimize or avoid acetaminophen in the 72 hours before and during busulfan.
- Your team may choose a different pain reliever during that window, or monitor you more closely and individualize your busulfan dose.
- Ask your pharmacist which pain or fever medicines are okay to use around your busulfan schedule.
Don't stop either drug on your own. This is very manageable when your care team plans the timing.
Management is individual — confirm any change with your pharmacist or prescriber.
Common questions
Can I take Acetaminophen And Codeine and Busulfan together?
The acetaminophen in your pain pill may slow busulfan's clearance, so tell your cancer team; they will usually just adjust the timing (avoiding acetaminophen within 72 hours of busulfan) and this is theoretical, not confirmed. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Acetaminophen And Codeine and Busulfan interaction?
It is rated moderate. Can be significant — usually manageable with monitoring.
How quickly could this interaction happen?
The documented onset is "delayed". Effects tend to build up gradually over days to weeks.
How is the Acetaminophen And Codeine and Busulfan interaction managed?
Keep taking both exactly as prescribed and let your oncology or transplant team know you use this acetaminophen-codeine product. The main step is timing: teams typically try to minimize or avoid acetaminophen in the 72 hours before and during busulfan. Your team may choose a different pain reliever during that window, or monitor you more closely and individualize your busulfan dose. Ask your pharm… 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 Busulfan 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 anything you'd monitor while I'm on both?
References (1)
- Product Information: Busulfex(R), busulfan. Orphan Medical Inc. Minnetonka, MN, 2003. DailyMed
Keep reading about Acetaminophen And Codeine
Keep reading about Busulfan
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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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