Acetaminophen And Codeine and Ziprasidone: 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
Ziprasidone
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.
You've been prescribed two medicines that can affect your brain and nervous system: acetaminophen with codeine (a pain reliever) and ziprasidone (Geodon, used for mood or thought disorders). Both can raise serotonin levels and both can slow down your central nervous system.
Used together, there's a small, mostly theoretical chance of two things: feeling extra drowsy, dizzy, or foggy, and a rare but serious reaction called serotonin syndrome (fast heart rate, high fever, sweating, shaking, muscle twitching, and confusion). This isn't common, and your care team can manage it. Take both exactly as prescribed, and call your pharmacist or doctor right away if these symptoms show up.
Effect: Additive risk of CNS depression and serotonin syndrome when ziprasidone is combined with the codeine-containing analgesic.
- Mechanism: Additive serotonergic activity plus additive CNS depression. Codeine is an opioid with weak serotonergic properties (and is a CYP2D6 prodrug converted to morphine); ziprasidone contributes serotonergic tone. Acetaminophen is not the driver here.
- Direction/magnitude: Pharmacodynamic (additive), not a defined AUC/Cmax change.
- Evidence: Theoretical. Severity: major. Onset: unspecified.
- Management: Monitor for mental status changes, autonomic instability, hyperthermia, neuromuscular findings (myoclonus, rigidity, hyperreflexia), and excess sedation. Discontinue both and give supportive care if serotonin syndrome emerges.
What happens
Increased risk for serotonin syndrome (hypertension, hyperthermia, myoclonus, mental status changes) and an increased risk of CNS depression
Interaction Deep Dive
Use care when ziprasidone is given together with serotonergic CNS depressants, since the combination may raise the likelihood of CNS depression and may also heighten the risk of serotonin syndrome, a condition that can be life-threatening. The presentation can involve altered mental status (for example, agitation, hallucinations, delirium, and coma), autonomic instability (for example, tachycardia, labile blood pressure, dizziness, diaphoresis, flushing, hyperthermia), neuromuscular findings (for example, tremor, rigidity, myoclonus, hyperreflexia, incoordination), seizures, and gastrointestinal effects (for example, nausea, vomiting, diarrhea). Every patient receiving ziprasidone should be watched for the development of serotonin syndrome. Should the symptoms described above appear, stop ziprasidone along with any accompanying serotonergic agents right away and begin supportive symptomatic care. When there is a clinical justification for using ziprasidone alongside other serotonergic drugs, advise patients about the elevated risk of serotonin syndrome and monitor them for symptoms12.
Why it happens (mechanism)
Additive serotonergic effects; additive CNS depression
How to manage this interaction
If both medicines are prescribed together, that can be appropriate, and the goal is simply to use them safely.
- Keep taking both as prescribed unless your prescriber tells you otherwise. Do not stop on your own.
- Your care team may monitor you more closely and tailor doses to you, especially when starting or increasing either drug.
- Watch for serotonin syndrome: fever, fast or irregular heartbeat, heavy sweating, shaking or muscle twitching, agitation, or confusion.
- Watch for too much sedation: heavy drowsiness, dizziness, or trouble thinking clearly.
- Get medical help promptly if these appear, and avoid alcohol or other sedatives without asking first.
Management is individual — confirm any change with your pharmacist or prescriber.
Literature reports
1 report — tap to read
a) A 67-year-old man with a background of rapid eye movement-behavior disorder, bipolar disorder, and Parkinson disease experienced serotonin syndrome after beginning tramadol 100 mg orally 3 times daily for knee and lower back pain following a fall. His home medications comprised amantadine 200 mg daily, carbidopa/levodopa 25/100 mg 4 times daily, divalproex sodium 1.25 g daily, clozapine 25 mg daily, and rasagiline 1 mg daily. At presentation, he was clammy and disoriented, showed a visible resting tremor, and described visual hallucinations. Amantadine toxicity was initially suspected, and ziprasidone 20 mg daily was initiated to address the hallucinations. The following day, the patient developed severe agitation accompanied by tachycardia, shivering with rapid involuntary movements, extreme diaphoresis, myoclonus, hyperactive bowel sounds, and hyperreflexia. Serotonin syndrome was diagnosed, and because of rhabdomyolysis and acute renal failure, the patient was intubated, sedated, and resuscitated with fluids; he recovered and was extubated on day 5. The introduction of ziprasidone was suspected to have contributed to the onset of serotonin syndrome in this case 3.
Common questions
Can I take Acetaminophen And Codeine and Ziprasidone together?
Taking acetaminophen with codeine alongside ziprasidone can add up to increase sedation and, rarely, serotonin syndrome, so take both as prescribed and seek help promptly if you notice fever, muscle twitching, confusion, or extreme drowsiness. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Acetaminophen And Codeine and Ziprasidone 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 Ziprasidone interaction managed?
If both medicines are prescribed together, that can be appropriate, and the goal is simply to use them safely. Keep taking both as prescribed unless your prescriber tells you otherwise. Do not stop on your own. Your care team may monitor you more closely and tailor doses to you, especially when starting or increasing either drug. Watch for serotonin syndrome: fever, fast or irregular heartbeat, he… 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 Ziprasidone 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 (3)
- Product Information: GEODON(R) intramuscular injection, ziprasidone mesylate intramuscular injection. Viatris Specialty LLC(per FDA), Morgantown, WV, 2025.
- Product Information: GEODON(R) oral capsules, ziprasidone oral capsules. Viatris Specialty LLC(per FDA), Morgantown, WV, 2025. DailyMed
- El-Okdi NS, Lumbrezer D, & Karanovic D: Serotonin syndrome after the use of tramadol and ziprasidone in a patient with a deep brain stimulator for Parkinson disease. Am J Ther 2014; 21(4):e97-e99. PubMed
Keep reading about Acetaminophen And Codeine
Keep reading about Ziprasidone
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