Anileridine 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
Anileridine
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.
Both of your medicines are opioids. The acetaminophen and codeine product contains codeine, and anileridine is a related opioid pain reliever. When two opioids are taken together, their effects add up. That can make you very drowsy, slow your breathing, and lower your alertness. There is also a smaller, more theoretical concern about too much serotonin activity, which can cause agitation, a fast heartbeat, shivering, or muscle twitching.
The good news is that your care team can manage this. They will use the lowest doses that work and watch you closely, especially when starting or changing a dose. Please talk with your pharmacist or doctor before making any change.
Additive CNS and respiratory depression from two concurrent opioids (codeine plus anileridine), with a theoretical additive serotonergic risk (serotonin syndrome).
- Direction: increased opioid effect (sedation, hypoventilation) via pharmacodynamic summation.
- Severity/evidence: major; evidence theoretical; onset unspecified.
- Management: avoid combination if possible; if required, use lowest effective dose and shortest duration, consider reducing dose of one agent.
- Monitor: sedation, respiratory rate/oxygenation, and signs of serotonin syndrome (clonus, hyperthermia, autonomic instability, agitation), especially at initiation and titration.
- Consider prescribing naloxone; discontinue codeine if serotonin syndrome is suspected.
What happens
Increased risk of respiratory and CNS depression and an increased risk of serotonin syndrome
Interaction Deep Dive
Avoid concomitant use of opioid cough medication formulations and CNS depressants2. Reserve the concomitant use of non-cough codeine products 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. Consider using a lower dose of codeine or the CNS depressant and closely monitor for sedation, respiratory depression, and signs and symptoms of serotonin syndrome. Additionally, concomitant use of opioids with serotonergic drugs has resulted in serotonin syndrome. If concomitant use is needed, carefully observe the patient, particularly during treatment initiation and dose adjustments. Consider prescribing naloxone for the emergency treatment of opioid overdose. Discontinue codeine if serotonin syndrome is suspected 134.
Why it happens (mechanism)
Additive CNS depression; additive serotonergic effects
How to manage this interaction
Keep taking both exactly as prescribed and do not stop either one on your own, but do flag this combination to your prescriber or pharmacist so they can review it.
- Your care team may avoid using both together when an alternative exists, or use the lowest dose for the shortest time that meets your needs.
- They may lower the dose of one opioid and monitor you more closely, especially when starting or adjusting doses.
- Ask whether a naloxone rescue kit is appropriate for you.
- Get help right away for slow or shallow breathing, extreme drowsiness, confusion, fever, shivering, or muscle twitching.
Management is individual — confirm any change with your pharmacist or prescriber.
Literature reports
5 reports — tap to read
a) One study found that the rate of emergency department visits linked to nonmedical use occurring between 2004 and 2011 and involving opioid analgesics together with benzodiazepines rose significantly from 11 to 34.2 per 100,000. Deaths from drug overdose attributable to prescribed and higher than prescribed doses of both classes of drugs likewise rose significantly from 0.6 to 1.7 per 100,000, and overdose deaths attributable to benzodiazepines rose significantly from 18% to 31% 2.
b) In a prospective cohort study, the rate of fatal overdoses involving the dispensing of both opioid analgesics and benzodiazepines was 10 times greater than with the dispensing of opioid analgesics on their own (7 versus 0.7 per 10,000 person years) 2.
c) In a cohort study using data from 2004 to 2009, the likelihood of fatal overdose rose significantly by 2.33 fold among patients receiving opioid analgesics who had a past benzodiazepine prescription, and rose by 3.86 fold among those with a current benzodiazepine prescription, when compared with patients receiving opioid analgesics who had no history of a benzodiazepine prescription. The risk of death from drug overdose grew as the daily benzodiazepine dose increased 2.
d) Observational studies have shown that using opioid analgesics and benzodiazepines together raises the risk of drug-related death compared with using opioid analgesics alone. Given their comparable pharmacological characteristics, it is reasonable to anticipate a similar risk when other CNS depressant drugs are used together with opioid analgesics 34.
e) Instances of serotonin syndrome, a condition that can be life-threatening, have been reported when opioids are used together with serotonergic drugs 34.
Common questions
Can I take Anileridine and Acetaminophen And Codeine together?
Taking two opioids (codeine and anileridine) together adds up their sedating and breathing-slowing effects and carries a theoretical serotonin risk; keep taking both as prescribed but have your care team review and monitor this closely. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Anileridine 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 Anileridine and Acetaminophen And Codeine interaction managed?
Keep taking both exactly as prescribed and do not stop either one on your own, but do flag this combination to your prescriber or pharmacist so they can review it. Your care team may avoid using both together when an alternative exists, or use the lowest dose for the shortest time that meets your needs. They may lower the dose of one opioid and monitor you more closely, especially when starting or… 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 Anileridine 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
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