Carphenazine and Acetaminophen And Codeine: 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
Carphenazine
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 contains codeine, an opioid, along with acetaminophen (Tylenol). Carphenazine is an older antipsychotic. Both of these can slow down your brain and your breathing. When you take them together, that calming effect can stack up and become too strong.
This can lead to feeling very drowsy, breathing that is slow or shallow, low blood pressure, and in serious cases much deeper problems. The good news is your care team can manage this safely. If both are truly needed, they can use the lowest dose for the shortest time and watch you closely. Please talk with your pharmacist or doctor before making any change.
Effect: Additive CNS and respiratory depression from combining codeine (opioid) with carphenazine (phenothiazine antipsychotic). Both agents independently depress CNS and respiratory drive; the mechanism is pharmacodynamic (additive), not a metabolic/PK interaction.
- Direction: Increased sedation, hypotension, respiratory depression, potential coma/death.
- Onset: Unspecified.
- Evidence: Theoretical, but severity is major given opioid + CNS depressant class data.
- Management: Reserve for patients lacking adequate alternatives. Use lowest effective dose and shortest duration; consider reducing dose of codeine or carphenazine. Monitor for sedation and respiratory depression. Consider prescribing naloxone.
What happens
An increased risk of respiratory and CNS depression
Interaction Deep Dive
Avoid concomitant use of opioid cough medication formulations and CNS depressants. Concomitant use of opioid analgesics with benzodiazepines has been associated with increased rates of emergency department visits and fatal overdose2. Concomitant use of codeine with CNS depressants can increase the risk of hypotension, respiratory depression, profound sedation, coma and death. Reserve concomitant prescribing of these drugs for use in patients for whom alternative treatment options are inadequate. Limit dosages and durations to the minimum required. Follow patients closely for signs of respiratory depression and sedation. If concomitant use is warranted, consider prescribing naloxone for the emergency treatment of opioid overdose 341.
Why it happens (mechanism)
Additive CNS depression
How to manage this interaction
If your care team decides you need both, this can be managed safely.
- Keep taking both as prescribed unless your prescriber tells you otherwise. Do not stop or change doses on your own.
- Your team may use the lowest dose for the shortest time and may adjust and individualize your doses.
- They may monitor you more closely for heavy drowsiness, slow or shallow breathing, confusion, or lightheadedness.
- Your prescriber may consider providing naloxone just in case.
Ask your pharmacist or doctor whether both are truly needed or if a safer alternative fits your situation.
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 occurred between 2004 and 2011 and involved opioid analgesics together with benzodiazepines rose significantly from 11 to 34.2 per 100,000. Deaths from drug overdose attributed to prescribed and above-prescribed doses of both drug classes likewise rose significantly from 0.6 to 1.7 per 100,000, and overdose deaths attributed to benzodiazepines rose significantly from 18% to 31% 2.
b) In a prospective cohort study, the rate of overdose deaths associated with the dispensing of both opioid analgesics and benzodiazepines was 10 times greater than that associated with the dispensing of opioid analgesics alone (7 versus 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 in patients receiving opioid analgesics who had a prior benzodiazepine prescription, and rose by 3.86 fold in those with a current benzodiazepine prescription, compared with patients receiving 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 comparable pharmacological properties, it is reasonable to anticipate a similar risk when other CNS depressant drugs are used concurrently with opioid analgesics 34.
Common questions
Can I take Carphenazine and Acetaminophen And Codeine together?
Codeine and carphenazine both depress the brain and breathing, so together they can cause dangerous sedation and slowed breathing. Use only if truly needed, at the lowest dose, and let your care team monitor you closely. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Carphenazine 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 Carphenazine and Acetaminophen And Codeine interaction managed?
If your care team decides you need both, this can be managed safely. Keep taking both as prescribed unless your prescriber tells you otherwise. Do not stop or change doses on your own. Your team may use the lowest dose for the shortest time and may adjust and individualize your doses. They may monitor you more closely for heavy drowsiness, slow or shallow breathing, confusion, or lightheadedness.… 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 Carphenazine 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 (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 Carphenazine
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