Acetaminophen And Codeine and Moricizine: Interaction Details
AI-assisted, pharmacist-reviewed · AI content regenerated Jul 11, 2026 · Source data updated Jul 1, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Acetaminophen And Codeine
Moricizine
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 has codeine, which is an opioid. Moricizine is a heart rhythm medicine that can also make you feel sleepy or slow. When you take these together, both can calm down your brain and slow your breathing at the same time. That adds up.
The main worries are feeling very drowsy, breathing too slowly, low blood pressure, or being hard to wake up. This concern is based on how the drugs work rather than lots of real-world reports, but because it can be serious, it is worth taking seriously. The good news: your care team can manage this by using the lowest dose needed for the shortest time and watching you closely. Please check with your pharmacist or doctor before combining them.
Effect: Additive CNS and respiratory depression when codeine (with acetaminophen) is combined with moricizine.
Mechanism: Pharmacodynamic (additive CNS depression), not primarily a metabolic/PK interaction. Neither drug is a prodrug concern that reverses the direction here (codeine's analgesic activation via CYP2D6 is separate; the risk here is additive sedation).
- Direction: Increased sedation, hypotension, respiratory depression, potential coma/death.
- Onset: Unspecified. Evidence: Theoretical. Severity: Major.
- Management: Avoid if possible; reserve for inadequate alternatives. Use lowest effective codeine dose and shortest duration. Monitor sedation and respiratory status. Consider naloxone availability.
What happens
An increased risk of respiratory and CNS depression
Interaction Deep Dive
Do not combine opioid cough medication products with CNS depressants. Co-administration of benzodiazepines and opioid analgesics has been linked to higher rates of fatal overdose and emergency department visits2. Using codeine together with CNS depressants may raise the likelihood of profound sedation, respiratory depression, hypotension, coma and death. Prescribe these agents together only for patients in whom other treatment choices prove insufficient. Keep both the dose and length of therapy to the lowest amount needed. Monitor patients carefully for indications of sedation and respiratory depression. Should combined use be justified, consider providing naloxone for emergency management of opioid overdose341.
Why it happens (mechanism)
Additive CNS depression
How to manage this interaction
Keep taking both exactly as prescribed and do not stop either one on your own. Bring this combination up with your pharmacist or prescriber so they can decide the safest plan.
- Your team may reserve this combination for when other options are not enough.
- They may use the lowest dose and shortest duration of codeine (or the other medicine) and adjust and individualize it for you.
- They may monitor you more closely for heavy drowsiness, slow or shallow breathing, and low blood pressure.
- They may consider prescribing naloxone as an emergency backup.
Get urgent help for very slow breathing, extreme sleepiness, or trouble waking up.
Management is individual — confirm any change with your pharmacist or prescriber.
Literature reports
4 reports — tap to read
a) In a study, emergency department visits related to nonmedical use that took place between 2004 and 2011 and involved both opioid analgesics and benzodiazepines rose significantly from 11 to 34.2 per 100,000. Drug overdose deaths attributable to prescribed and higher than prescribed doses of both drug classes likewise increased significantly from 0.6 to 1.7 per 100,000, and overdose deaths attributable to benzodiazepines increased significantly from 18% to 31% 2.
b) In a prospective cohort study, the rate of overdose deaths involving dispensing of both opioid analgesics and benzodiazepines was 10 times greater than that associated with dispensing of opioid analgesics alone (7 vs 0.7 per 10,000 person years) 2.
c) In a cohort study using data from 2004 to 2009, the risk of fatal overdose rose significantly by 2.33 fold among patients taking opioid analgesics who had a history of a benzodiazepine prescription and rose by 3.86 fold among those with a current benzodiazepine prescription, compared with patients taking opioid analgesics who had no history of a benzodiazepine prescription. The risk of drug overdose deaths grew as daily benzodiazepine doses increased 2.
d) Observational studies have shown that using opioid analgesics and benzodiazepines together raises the risk of drug-related mortality compared with using opioid analgesics alone. Given similar pharmacological properties, it is reasonable to anticipate comparable risk when other CNS depressant drugs are used together with opioid analgesics 34.
Common questions
Can I take Acetaminophen And Codeine and Moricizine together?
Codeine plus moricizine can add up to dangerous drowsiness and slowed breathing, so this combination is best avoided unless your care team decides it is needed, then used at the lowest dose with close monitoring. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Acetaminophen And Codeine and Moricizine 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 Moricizine interaction managed?
Keep taking both exactly as prescribed and do not stop either one on your own. Bring this combination up with your pharmacist or prescriber so they can decide the safest plan. Your team may reserve this combination for when other options are not enough. They may use the lowest dose and shortest duration of codeine (or the other medicine) and adjust and individualize it for you. They may monitor yo… 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 Moricizine 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 (4)
- Product Information: CARISOPRODOL, ASPIRIN, CODEINE PHOSPHATE oral tablets, carisoprodol, aspirin, codeine phosphate oral tablets. Ingenus Pharmaceuticals LLC (per DailyMed), Orlando, FL, 2021. DailyMed
- US Food and Drug Administration (FDA): Drug Safety Communications: FDA warns about serious risks and death when combining opioid pain or cough medicines with benzodiazepines; requires its strongest warning. US Food and Drug Administration (FDA). Silver Spring, MD. 2016.
- 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 Moricizine
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