Oxycodone and Amitriptyline: Interaction Details
AI-assisted, pharmacist-reviewed · AI content regenerated Jul 11, 2026 · Source data updated Jul 2, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Amitriptyline
Oxycodone
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 amitriptyline (a tricyclic antidepressant) and oxycodone (an opioid pain medicine) can gently boost a brain chemical called serotonin. Taking them together can, in rare cases, raise serotonin too high. That is called serotonin syndrome, and signs include shakiness, sweating, a fast heartbeat, restlessness, or confusion.
These two also both slow down the gut and bladder. Together that can mean stronger constipation and trouble urinating, and rarely the gut can nearly stop moving. The good news: this is a possible risk, not a sure thing. Your care team can manage it by watching you closely, especially when you first start or change a dose. Keep taking both as prescribed and call your doctor or pharmacist if anything feels off.
Direction/mechanism: Additive risk, not a clearance change. Amitriptyline (serotonergic TCA with strong anticholinergic activity) plus oxycodone (opioid with serotonergic activity) produces:
- Additive serotonergic effect to serotonin syndrome.
- Additive reduction in GI/GU motility to constipation, urinary retention, and potential paralytic ileus.
Evidence: theoretical; severity: major; onset: unspecified, highest at initiation and dose changes. Neither is the affected substrate here, so no AUC/Cmax shift is implicated.
Management: Monitor for serotonin syndrome (autonomic instability, hyperreflexia, clonus, mental status change), severe constipation, and urinary retention. Consider prophylactic bowel regimen. Discontinue oxycodone if serotonin syndrome is suspected. Dose may be individualized by the care team.
What happens
Increased risk of paralytic ileus and an increased risk of serotonin syndrome
Interaction Deep Dive
Taking opioids like oxyCODONE together with serotonergic agents can lead to serotonin syndrome. Furthermore, combining oxyCODONE with anticholinergic medications may heighten the likelihood of urinary retention and severe constipation, potentially progressing to paralytic ileus. When such combined therapy is necessary, keep a close watch on the patient for urinary retention, severe constipation, and the signs and symptoms of serotonin syndrome, especially when starting treatment and adjusting the dose. If serotonin syndrome is suspected, stop oxyCODONE. Serotonin syndrome, a condition that can be life-threatening, has been documented in cases where opioids were used concurrently with serotonergic drugs12.
Why it happens (mechanism)
Additive effects on gastric motility; additive serotonergic effects
How to manage this interaction
If your prescriber has you on both, that can be appropriate. The plan is to keep taking both as prescribed while your team watches for problems, especially when starting or changing a dose.
- Watch for serotonin syndrome: agitation, sweating, tremor, fast heartbeat, muscle twitching, or confusion. Get help right away if these appear.
- Watch your gut and bladder: report severe constipation, no bowel movements, belly swelling or pain, or trouble urinating.
- The dose may be adjusted and individualized by your care team, and they may monitor you more closely.
Do not start, stop, or change either medicine on your own. Ask your pharmacist or prescriber about a stool softener or laxative plan.
Management is individual — confirm any change with your pharmacist or prescriber.
Literature reports
1 report — tap to read
Common questions
Can I take Oxycodone and Amitriptyline together?
Combining amitriptyline and oxycodone can add up to higher risks of serotonin syndrome and severe constipation or urinary retention (possibly paralytic ileus), so keep taking both as prescribed but watch for symptoms and report them, especially when starting or changing a dose. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Oxycodone and Amitriptyline 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 Oxycodone and Amitriptyline interaction managed?
If your prescriber has you on both, that can be appropriate. The plan is to keep taking both as prescribed while your team watches for problems, especially when starting or changing a dose. Watch for serotonin syndrome: agitation, sweating, tremor, fast heartbeat, muscle twitching, or confusion. Get help right away if these appear. Watch your gut and bladder: report severe constipation, no bowel m… 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 Oxycodone or Amitriptyline 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: OXYCONTIN(R) oral extended-release tablets, oxycodone HCl oral extended-release tablets. Purdue Pharma LP (per FDA), Stamford, CT, 2023. DailyMed
- Product Information: PERCODAN(R) oral tablets, oxycodone aspirin oral tablets. Endo Pharmaceuticals Inc. (per FDA), Malvern, PA, 2023.
Keep reading about Amitriptyline
Keep reading about Oxycodone
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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