Acetaminophen And Codeine and Tiotropium: 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
Tiotropium
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.
You've been prescribed acetaminophen with codeine (a pain medicine) and tiotropium (an inhaler for your lungs). Both of these can slow down your gut and make it harder to empty your bladder. When you take them together, that slowing effect can add up. In rare cases, the gut can slow so much that it nearly stops, which is called paralytic ileus.
The good news is this concern is mostly theoretical, meaning it hasn't been strongly seen in real patients. Watch for bad constipation, a swollen or painful belly, or trouble urinating, and let your doctor or pharmacist know. Your care team can keep an eye on this and help manage it.
Effect: Additive risk of severe constipation, urinary retention, and potentially paralytic ileus when codeine (an opioid with anticholinergic-like GI effects) is combined with tiotropium (an inhaled long-acting muscarinic antagonist).
- Mechanism: Additive reduction in gastric/GI motility and bladder tone (PD interaction).
- Direction: Increased anticholinergic-type adverse effects; not a metabolic (CYP) interaction.
- Onset: Unspecified.
- Evidence: Theoretical; systemic anticholinergic burden from inhaled tiotropium is typically low.
- Management: Monitor for reduced gastric motility, abdominal distension, and urinary retention. Encourage hydration and bowel regimen if opioid use is prolonged.
What happens
An increased risk of paralytic ileus
Interaction Deep Dive
Using codeine together with anticholinergic agents can heighten the likelihood of urinary retention and/or severe constipation, potentially progressing to paralytic ileus. When codeine and anticholinergic drugs are administered concurrently, 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 care team tells you otherwise. Because both can slow your gut and bladder, your team's main tool here is watching for warning signs and acting early.
- Watch for severe constipation, a bloated or painful belly, nausea, or trouble passing urine.
- Contact your pharmacist or doctor promptly if these happen.
- Ask whether a stool softener or laxative and staying well hydrated would help, especially if you'll use the pain medicine for more than a few days.
Your care team can adjust and individualize your plan and monitor you more closely to keep this safe.
Management is individual — confirm any change with your pharmacist or prescriber.
Common questions
Can I take Acetaminophen And Codeine and Tiotropium together?
Taking codeine with tiotropium can add up to slow your gut and bladder, so watch for bad constipation, belly pain, or trouble urinating and tell your care team. This risk is theoretical, but keep both medicines going unless your doctor says otherwise. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Acetaminophen And Codeine and Tiotropium 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 Tiotropium interaction managed?
Keep taking both medicines as prescribed unless your care team tells you otherwise. Because both can slow your gut and bladder, your team's main tool here is watching for warning signs and acting early. Watch for severe constipation, a bloated or painful belly, nausea, or trouble passing urine. Contact your pharmacist or doctor promptly if these happen. Ask whether a stool softener or laxative and… 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 Tiotropium 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 Tiotropium
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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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