Acetaminophen And Codeine and Glycopyrrolate: 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
Glycopyrrolate
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, which can slow down your gut and make you constipated. Glycopyrrolate is a type of drug (called an anticholinergic) that also slows the gut and can make it harder to empty your bladder. When you take both, these slowing effects can add up. In rare cases, the bowel can slow so much that it nearly stops moving, which is called a paralytic ileus.
The good news is this is a theoretical concern, and your care team can manage it easily. Watch for hard stools, no bowel movements, a swollen or painful belly, or trouble urinating, and let your pharmacist or doctor know if these happen.
Effect: Additive reduction in GI motility with concurrent codeine (opioid) and glycopyrrolate (antimuscarinic), increasing risk of severe constipation, urinary retention, and potentially paralytic ileus. This is a pharmacodynamic (additive), not pharmacokinetic, interaction.
- Direction: Combined anticholinergic/opioid effects amplify GI slowing and urinary retention.
- Severity/Evidence: Rated major, but substantiation is theoretical; onset unspecified.
- Management: Monitor for reduced gastric motility, abdominal distension, and urinary retention. Consider prophylactic bowel regimen. Dose and duration may be individualized 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 medications as prescribed unless your care team tells you otherwise. Because both can slow the bowel and bladder, your team may watch you more closely and tailor your doses.
- Watch for constipation, no bowel movements, belly swelling or pain, or trouble urinating.
- Ask your pharmacist whether a stool softener, fluids, or fiber could help prevent constipation.
- Report any of the above symptoms promptly to your pharmacist or prescriber.
- Do not start, stop, or change either medicine on your own; let your care team adjust things.
Management is individual — confirm any change with your pharmacist or prescriber.
Common questions
Can I take Acetaminophen And Codeine and Glycopyrrolate together?
Taking codeine with glycopyrrolate can add up to worse constipation and possible urinary retention, so watch for these signs and tell your care team. The risk is theoretical, and your team can manage it with monitoring and simple steps. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Acetaminophen And Codeine and Glycopyrrolate 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 Glycopyrrolate interaction managed?
Keep taking both medications as prescribed unless your care team tells you otherwise. Because both can slow the bowel and bladder, your team may watch you more closely and tailor your doses. Watch for constipation, no bowel movements, belly swelling or pain, or trouble urinating. Ask your pharmacist whether a stool softener, fluids, or fiber could help prevent constipation. Report any of the above… 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 Glycopyrrolate 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 Glycopyrrolate
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.
Check another combination
Our instant two-drug interaction checker is almost here.
Still have questions about this combination?
Every question gets a real answer from a licensed pharmacist — free, and usually within a day.
Ask the pharmacist