Amitriptyline and Acetaminophen And Codeine: Interaction Details
AI-assisted, pharmacist-reviewed · AI content regenerated Jul 11, 2026 · Source data updated Jun 30, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Acetaminophen And Codeine
Amitriptyline
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 Tylenol with codeine (a pain medicine) along with amitriptyline (often used for depression, nerve pain, or sleep). Taking both together can add up in two ways.
First, both can affect a body chemical called serotonin, and in rare cases too much serotonin causes a reaction with agitation, sweating, shaking, fast heartbeat, or confusion. Second, both can slow the gut and bladder, which can lead to bad constipation or trouble urinating. In severe cases the bowel can nearly stop moving. This is a theoretical concern, not something that happens to everyone. Your care team can manage it by watching you closely, especially when you start or change doses. Call them if you feel these symptoms.
Additive pharmacodynamic interaction. Codeine has weak serotonergic activity and amitriptyline is serotonergic, so combined use raises the theoretical risk of serotonin syndrome. Both agents also slow GI motility (opioid effect plus TCA anticholinergic effect), giving additive risk of severe constipation, urinary retention, and potentially paralytic ileus.
- Direction: additive/increased adverse effect, not a CYP-clearance change.
- Evidence: theoretical; severity: major; onset unspecified.
- Management: monitor for serotonin syndrome (autonomic instability, clonus, hyperthermia, agitation), constipation, and urinary retention, especially at initiation and dose adjustment. Discontinue codeine if serotonin syndrome is suspected.
What happens
Increased risk of paralytic ileus; increased risk of serotonin syndrome
Interaction Deep Dive
Concomitant use of opioids, such as codeine, with serotonergic drugs has resulted in serotonin syndrome. Additionally, the concomitant use of codeine with anticholinergic drugs may increase the risk of urinary retention and severe constipation, which may lead to paralytic ileus. If concomitant use is needed, closely monitor the patient for urinary retention, severe constipation, and signs and symptoms of serotonin syndrome1. during treatment initiation and dose adjustment. Discontinue codeine if serotonin syndrome is suspected 2.
Why it happens (mechanism)
Additive effects on gastric motility; additive serotonergic effects
How to manage this interaction
If your care team decides you need both medicines, they can manage this safely.
- Keep taking both as prescribed unless your doctor or pharmacist tells you otherwise.
- Doses may be adjusted and individualized by your care team, and they may monitor you more closely when starting or changing either drug.
- Watch for severe constipation, trouble urinating, or belly pain and bloating, and report these promptly.
- Get urgent help for serotonin syndrome signs: agitation, shaking, sweating, fast heartbeat, fever, or confusion.
Bring any new symptoms to your pharmacist or prescriber right away.
Management is individual — confirm any change with your pharmacist or prescriber.
Common questions
Can I take Amitriptyline and Acetaminophen And Codeine together?
Using Tylenol with codeine alongside amitriptyline can add up to cause severe constipation, urinary retention, or rarely serotonin syndrome, so stay alert for those symptoms and let your care team monitor you, especially when doses change. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Amitriptyline 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 Amitriptyline and Acetaminophen And Codeine interaction managed?
If your care team decides you need both medicines, they can manage this safely. Keep taking both as prescribed unless your doctor or pharmacist tells you otherwise. Doses may be adjusted and individualized by your care team, and they may monitor you more closely when starting or changing either drug. Watch for severe constipation, trouble urinating, or belly pain and bloating, and report these pro… 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.
From our Q&A
Real reader questions about these medications, each personally answered by our pharmacist:
Questions for your pharmacist
- Does my dose of Amitriptyline 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 (2)
- 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
Keep reading about Acetaminophen And Codeine
Keep reading about Amitriptyline
These medications also interact with supplements
Prescription drugs aren't the whole picture — herbal and dietary supplements can interact with them too. From the evidence-graded Natural Medicines database:
major · moderate · minor — check everything you take with our drug–supplement interaction checker.
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