Dimenhydrinate 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
Dimenhydrinate
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 has codeine in it, and Dramamine (dimenhydrinate) is used for nausea and motion sickness. Both can slow down your gut and your bladder. Codeine is well known for causing constipation, and dimenhydrinate has a drying effect that can add to that. Together, they may make it harder to have a bowel movement or to fully empty your bladder.
In rare cases, a very slow gut can become a serious problem where the bowel stops moving. This is a possible risk, not something that happens to everyone. Watch for belly pain, bloating, no bowel movements, or trouble urinating, and tell your care team. They can easily manage this.
Effect: Additive reduction in GI and bladder motility, raising the theoretical risk of severe constipation, urinary retention, and (rarely) paralytic ileus.
Mechanism: Codeine (an opioid) reduces gut motility; dimenhydrinate carries anticholinergic activity that further slows GI transit and bladder emptying. This is a pharmacodynamic (additive), not pharmacokinetic, interaction.
- Direction: Increased anticholinergic/constipating burden.
- Severity/evidence: Major severity, theoretical substantiation; onset unspecified.
- Management: Monitor for reduced gastric motility, abdominal distension, and urinary retention. Consider bowel regimen and dose individualization by the care team.
What happens
An increased risk of paralytic ileus
Interaction Deep Dive
Concomitant use of codeine with anticholinergic drugs may increase the risk of urinary retention and/or severe constipation, which may lead to paralytic ileus. Monitor patients for signs of urinary retention or reduced gastric motility when codeine is used concomitantly with anticholinergic drugs1.
Why it happens (mechanism)
Additive effects on gastric motility
How to manage this interaction
Keep taking both medicines as prescribed unless your prescriber or pharmacist tells you otherwise. This risk is considered theoretical, but it is worth being aware of.
- Watch for warning signs: no bowel movements for a few days, hard stools, belly bloating or pain, or trouble passing urine.
- Support your gut: ask your care team whether staying hydrated, moving around, or a stool softener would help.
- Timing and dose: your team may adjust and individualize your doses or monitor you more closely.
- Report promptly: tell your pharmacist or doctor if any warning signs appear.
Management is individual — confirm any change with your pharmacist or prescriber.
Common questions
Can I take Dimenhydrinate and Acetaminophen And Codeine together?
Taking codeine (in your acetaminophen-codeine product) with dimenhydrinate can add up to more constipation and possible urinary retention, and rarely a stalled bowel. Watch for belly bloating, no bowel movements, or trouble urinating, and let your care team know. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Dimenhydrinate and Acetaminophen And Codeine 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 Dimenhydrinate and Acetaminophen And Codeine interaction managed?
Keep taking both medicines as prescribed unless your prescriber or pharmacist tells you otherwise. This risk is considered theoretical, but it is worth being aware of. Watch for warning signs: no bowel movements for a few days, hard stools, belly bloating or pain, or trouble passing urine. Support your gut: ask your care team whether staying hydrated, moving around, or a stool softener would help.… 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.
From our Q&A
Real reader questions about these medications, each personally answered by our pharmacist:
Questions for your pharmacist
- Does my dose of Dimenhydrinate 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: CARISOPRODOL, ASPIRIN, CODEINE PHOSPHATE oral tablets, carisoprodol, aspirin, codeine phosphate oral tablets. Ingenus Pharmaceuticals LLC (per DailyMed), Orlando, FL, 2021. DailyMed
Keep reading about Acetaminophen And Codeine
Keep reading about Dimenhydrinate
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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:
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