Acetaminophen And Codeine and Cholestyramine: 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
Cholestyramine
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.
You're taking acetaminophen with codeine (a pain reliever) along with cholestyramine (a medicine that lowers cholesterol or eases certain diarrhea). Cholestyramine works like a sponge in your gut, and it can grab onto the acetaminophen before your body absorbs it. That means less acetaminophen gets into your blood, so it may not relieve pain or lower a fever as well.
The good news is this is easy to work around. The usual fix is simple timing: taking the two medicines a few hours apart. Talk with your pharmacist or doctor about the best schedule for you, and don't stop either medicine on your own.
Effect: Reduced acetaminophen efficacy via decreased GI absorption. Cholestyramine, an anion-exchange resin, binds acetaminophen in the gut lumen, lowering plasma concentrations. (Codeine is not the focus here; the interaction involves the acetaminophen component.)
- Direction: Reduces acetaminophen exposure (lower Cmax/AUC) and analgesic/antipyretic effect.
- Onset: Rapid.
- Evidence: Probable; demonstrated in a controlled study.
- Severity: Minor.
- Management: Separate dosing. Give acetaminophen 1 hour before or 3 to 4 hours after cholestyramine. Monitor for adequate pain/fever control and adjust as needed.
What happens
Decreased acetaminophen effectiveness
Interaction Deep Dive
In a controlled study the concurrent use of cholestyramine and acetaminophen resulted in significantly lower plasma levels when compared to acetaminophen given alone1.
Why it happens (mechanism)
Decreased acetaminophen absorption
How to manage this interaction
This is a manageable, minor interaction that comes down to timing. You can keep taking both medicines as prescribed.
- The typical approach is to space the doses apart: take acetaminophen (with codeine) about 1 hour before or 3 to 4 hours after your cholestyramine.
- Watch whether your pain or fever relief seems weaker than expected.
- Ask your pharmacist or prescriber to confirm the best schedule for your specific doses, and let them know if the pain relief doesn't feel adequate so they can adjust and individualize your plan.
Management is individual — confirm any change with your pharmacist or prescriber.
Common questions
Can I take Acetaminophen And Codeine and Cholestyramine together?
Cholestyramine can bind acetaminophen in the gut and make it less effective, but simply separating the doses (acetaminophen 1 hour before or 3 to 4 hours after cholestyramine) usually solves it. Keep taking both as prescribed and confirm the timing with your pharmacist. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Acetaminophen And Codeine and Cholestyramine interaction?
It is rated minor. Usually limited clinical impact.
How quickly could this interaction happen?
The documented onset is "rapid". Effects can appear quickly, often within about 24 hours of combining the drugs.
How is the Acetaminophen And Codeine and Cholestyramine interaction managed?
This is a manageable, minor interaction that comes down to timing. You can keep taking both medicines as prescribed. The typical approach is to space the doses apart: take acetaminophen (with codeine) about 1 hour before or 3 to 4 hours after your cholestyramine. Watch whether your pain or fever relief seems weaker than expected. Ask your pharmacist or prescriber to confirm the best schedule for y… 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 Acetaminophen And Codeine or Cholestyramine 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)
- Dordoni B, Willson RA, Thompson RP, et al: Reduction of absorption of paracetamol by activated charcoal and cholestyramine: a possible therapeutic measure. Br Med J 1973; 3:86-87. PubMed
Keep reading about Acetaminophen And Codeine
Keep reading about Cholestyramine
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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