Carisoprodol 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
Carisoprodol
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 acetaminophen with codeine is an opioid pain reliever, and carisoprodol (Soma) is a muscle relaxer. Both slow down your brain and nervous system. Taken together, they can add up and make you very sleepy, slow your breathing, and lower your blood pressure. In serious cases this can be dangerous. They can also team up to slow your gut and bladder, leading to bad constipation or trouble urinating.
The good news: your care team knows how to handle this. They may use the lowest dose for the shortest time and watch you closely. Watch for heavy drowsiness, slowed breathing, or feeling faint, and call your doctor or pharmacist if you notice these.
Additive CNS depression between codeine (opioid) and carisoprodol (centrally acting skeletal muscle relaxant). Both agents depress the CNS, and carisoprodol's metabolite meprobamate contributes further sedation.
- Direction/effect: Increased risk of profound sedation, respiratory depression, hypotension, coma, and death; also enhanced risk of urinary retention and severe constipation progressing to paralytic ileus.
- Evidence: Theoretical (pharmacodynamic), rated major.
- Onset: Unspecified.
- Management: Reserve for patients lacking adequate alternatives; use lowest effective dose and shortest duration; reduce codeine and/or carisoprodol dose as needed; monitor sedation, respiratory rate, GI motility, and urinary output; consider prescribing naloxone.
What happens
Increased risk of urinary retention and/or severe constipation leading to paralytic ileus, increased risk of profound sedation, respiratory depression, coma and death
Interaction Deep Dive
Concomitant use of dihydrocodeine with drugs that are skeletal muscle relaxants and CNS depressants can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death. Reserve the concomitant use of dihydrocodeine and CNS depressants to patients for whom alternatives are inadequate. If concomitant use is necessary, use the lowest dose and shortest duration necessary to achieve treatment goals. Additionally, concomitant use may increase the risk of urinary retention and/or severe constipation, which can lead to paralytic ileus. Monitor for signs and symptoms of urinary retention, reduced gastric motility, respiratory depression and sedation. Respiratory depression may be greater than otherwise expected with concomitant muscle relaxant and hence decrease the dosage of dihydrocodeine and/or the muscle relaxant as necessary. Inform patients and caregivers of this potential interaction and educate them on the signs and symptoms of respiratory depression (including sedation). If concomitant use is warranted, consider prescribing naloxone for the emergency treatment of opioid overdose12.
Why it happens (mechanism)
Enhanced neuromuscular blockade; additive CNS depression
How to manage this interaction
Keep taking both exactly as prescribed unless your prescriber tells you otherwise. This combination is used when other options aren't enough, and your team can manage it safely.
- Your doctor may prescribe the lowest dose for the shortest time, and either drug's dose may be adjusted and individualized by your care team.
- They may monitor you more closely for excess drowsiness, slowed breathing, constipation, or trouble urinating.
- Ask your pharmacist whether having naloxone on hand is right for you.
- Avoid alcohol or other sedatives, and call your care team right away if breathing feels slow, you can't stay awake, or your bowels/bladder stop working.
Management is individual — confirm any change with your pharmacist or prescriber.
Literature reports
1 report — tap to read
a) Observational research has shown that using opioid analgesics together with benzodiazepines raises the likelihood of drug-related death when compared with using opioid analgesics by themselves. Given the comparable pharmacological characteristics, it is reasonable to anticipate a similar risk when other CNS depressant medications are combined with opioid analgesics 12.
Common questions
Can I take Carisoprodol and Acetaminophen And Codeine together?
Combining acetaminophen/codeine with carisoprodol adds up their sedating effects and can cause dangerous drowsiness, slowed breathing, constipation, or urinary retention. Use only as prescribed, at the lowest dose, and tell your care team about any heavy drowsiness or slow breathing. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Carisoprodol 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 Carisoprodol and Acetaminophen And Codeine interaction managed?
Keep taking both exactly as prescribed unless your prescriber tells you otherwise. This combination is used when other options aren't enough, and your team can manage it safely. Your doctor may prescribe the lowest dose for the shortest time, and either drug's dose may be adjusted and individualized by your care team. They may monitor you more closely for excess drowsiness, slowed breathing, const… 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 Carisoprodol 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 (2)
- Product Information: Codeine sulfate oral solution, codeine sulfate oral solution. Hikma Pharmaceuticals USA Inc(per FDA), Berkeley Heights, NJ, 2023. DailyMed
- Product Information: Codeine sulfate oral tablets, codeine sulfate oral tablets. Hikma Pharmaceuticals USA Inc. (per FDA), Berkeley Heights, NJ, 2023. DailyMed
Keep reading about Acetaminophen And Codeine
Keep reading about Carisoprodol
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