Acetaminophen And Codeine and Meptazinol: 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
Meptazinol
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.
These two medicines usually shouldn't be taken together. Your first medicine has codeine, a regular opioid pain reliever. Meptazinol is a different kind of opioid that both turns receptors on and blocks them. Because it can block the same spots codeine uses, it can actually make codeine work less well for pain, and if your body is used to codeine, it can even trigger withdrawal (things like sweating, stomach cramps, and feeling anxious).
At the same time, both drugs can slow your breathing and make you very sleepy, so taking both can add up. The good news is your care team can manage this safely, often by choosing a different medicine. Please talk with your doctor or pharmacist before combining them.
Direction: Combining codeine (full mu-opioid agonist) with meptazinol (mixed agonist/antagonist, partial agonist) may reduce codeine's analgesic effect via competitive opioid receptor antagonism and may precipitate withdrawal in opioid-dependent patients. Concurrently, additive CNS depression raises risk of hypotension, respiratory depression, profound sedation, coma, and death.
- Mechanism: opioid receptor antagonism plus additive CNS depression.
- Evidence: theoretical; severity major.
- Management: avoid concurrent use. If unavoidable, use lowest effective dose and shortest duration, reduce dose of one agent, monitor closely for sedation/respiratory depression, and consider prescribing naloxone.
Note codeine is a prodrug requiring CYP2D6 activation, but this interaction is pharmacodynamic, not metabolic.
What happens
An increased risk of hypotension, respiratory depression, profound sedation, coma and reduced analgesic effect or precipitation of withdrawal symptoms
Interaction Deep Dive
Do not use codeine together with a mixed opioid agonist/antagonist or a partial agonist opioid analgesic like meptazinol, since doing so can diminish codeine's analgesic effect and may trigger withdrawal symptoms1. Likewise, avoid combining codeine (opioid) cough medication formulations with meptazinol (CNS depressant)3. Taking these agents together can also heighten the risk of hypotension, respiratory depression, profound sedation, coma, and death. Limit the combined use of non-cough codeine products with meptazinol to patients for whom other options are inadequate. When such combined use cannot be avoided, employ the lowest dose and shortest duration required to meet treatment goals. A reduced dose of either codeine or meptazinol may be considered, along with close monitoring for sedation and respiratory depression. Should concurrent use be justified, consider prescribing naloxone for the emergency management of opioid overdose42.
Why it happens (mechanism)
Additive CNS depression; opioid receptor antagonism
How to manage this interaction
Keep taking your medicines as prescribed and do not stop or change anything on your own. Because these two can work against each other and also stack up their sedating effects, care teams usually try to avoid using them together.
- Your prescriber may choose an alternative pain medicine instead.
- If both are truly needed, your team may use the lowest dose and shortest time possible, adjust and individualize the dose, and monitor you more closely for heavy sleepiness or slowed breathing.
- They may also prescribe naloxone for emergency use.
Call your pharmacist or doctor right away if you notice extreme drowsiness, very slow breathing, or withdrawal symptoms like sweating, cramps, or anxiety.
Management is individual — confirm any change with your pharmacist or prescriber.
Common questions
Can I take Acetaminophen And Codeine and Meptazinol together?
Codeine and meptazinol generally shouldn't be combined because meptazinol can block codeine's pain relief and trigger withdrawal, while both together can dangerously slow breathing; ask your doctor or pharmacist about a safer option. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Acetaminophen And Codeine and Meptazinol 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 Meptazinol interaction managed?
Keep taking your medicines as prescribed and do not stop or change anything on your own. Because these two can work against each other and also stack up their sedating effects, care teams usually try to avoid using them together. Your prescriber may choose an alternative pain medicine instead. If both are truly needed, your team may use the lowest dose and shortest time possible, adjust and indivi… 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 Meptazinol 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: Codeine sulfate oral tablets, codeine sulfate oral tablets. West-Ward Pharmaceuticals Corp (per DailyMed), Eatontown, NJ, 2016. DailyMed
- 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
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