Acetaminophen And Codeine and Oxitropium Bromide: 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
Oxitropium Bromide
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, an opioid that can slow down your gut and make it harder to have a bowel movement or empty your bladder. Oxitropium is an inhaled medicine that relaxes airways, but it's also an anticholinergic, which means it can slow the gut and bladder too.
When you take both, these slowing effects can add up. In rare cases, the gut can get so sluggish it nearly stops, a problem called paralytic ileus. This is a theoretical concern, not something that happens to most people. Watch for constipation, bloating, belly pain, or trouble urinating, and let your care team know. They can manage this easily by keeping an eye on you.
Effect: Additive reduction in GI and urinary tract motility from codeine (opioid) plus oxitropium bromide (inhaled anticholinergic), theoretically increasing risk of severe constipation, urinary retention, and paralytic ileus.
Mechanism: Additive slowing of gastric/GI motility (opioid mu-receptor effects plus antimuscarinic action).
- Direction: Additive PD interaction, increased anticholinergic/constipating burden.
- Evidence: Theoretical; severity rated major.
- Onset: Unspecified.
- Management: Monitor for reduced gastric motility, abdominal distension, and urinary retention. Consider bowel regimen. Dosing individualized by the care team.
What happens
An increased risk of paralytic ileus
Interaction Deep Dive
Taking codeine together with anticholinergic agents can raise the likelihood of urinary retention and/or serious constipation, potentially progressing to paralytic ileus. When these anticholinergic drugs are combined with codeine, watch patients for indications of urinary retention or diminished gastric motility1.
Why it happens (mechanism)
Additive effects on gastric motility
How to manage this interaction
Keep taking both medicines as prescribed unless your prescriber tells you otherwise. The main thing here is watching for a sluggish gut or bladder.
- Watch for constipation, bloating, belly pain, nausea, or trouble urinating and report these to your pharmacist or doctor.
- Your care team may monitor you more closely for signs of reduced gut movement or urinary retention.
- Staying hydrated and active can help, and your team may suggest a bowel routine if constipation becomes a problem.
- Any dose changes should be individualized by your care team, not made on your own.
Management is individual — confirm any change with your pharmacist or prescriber.
Common questions
Can I take Acetaminophen And Codeine and Oxitropium Bromide together?
Taking codeine with the anticholinergic oxitropium can add up to worse constipation or urinary retention, and rarely a stalled gut (paralytic ileus). Keep taking both as prescribed, watch for belly or bladder symptoms, and report them to your care team. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Acetaminophen And Codeine and Oxitropium Bromide 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 Oxitropium Bromide interaction managed?
Keep taking both medicines as prescribed unless your prescriber tells you otherwise. The main thing here is watching for a sluggish gut or bladder. Watch for constipation, bloating, belly pain, nausea, or trouble urinating and report these to your pharmacist or doctor. Your care team may monitor you more closely for signs of reduced gut movement or urinary retention. Staying hydrated and active ca… 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 Oxitropium Bromide 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
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