Amitriptyline and Levorphanol: 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
Levorphanol
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 can nudge the same body systems in the same direction, so taking them together can add up. Amitriptyline (Elavil) and levorphanol (Xyvona) can each raise serotonin, a brain chemical. Too much serotonin at once can cause a reaction called serotonin syndrome, with things like agitation, sweating, shivering, fast heartbeat, or muscle twitching.
Amitriptyline also has drying (anticholinergic) effects, and opioids like levorphanol slow the gut. Together they can worsen constipation and make it hard to pee, which in rare cases can lead to a serious bowel blockage. The good news: your care team can manage this safely by watching you closely, especially when you start or change a dose. Please don't stop either drug on your own, just talk with your pharmacist or doctor.
Effect: Additive risk of serotonin syndrome plus additive anticholinergic/opioid-related GI and urinary effects (constipation, urinary retention, potential paralytic ileus).
Mechanism: Both agents have serotonergic activity; amitriptyline's anticholinergic load combines with levorphanol's opioid-induced reduction in gut motility. This is a PD interaction (not enzyme/prodrug driven).
Evidence: Theoretical; severity rated major; onset unspecified.
- Observe for serotonin syndrome (autonomic instability, clonus, hyperreflexia, mental status change), especially at initiation and dose changes.
- Monitor bowel function and urinary output; consider prophylactic bowel regimen.
- Doses may be individualized by the care team; discontinue levorphanol if serotonin syndrome is suspected.
What happens
An increased risk of paralytic ileus and an increased risk of serotonin syndrome
Interaction Deep Dive
When levorphanol is given together with another serotonergic agent, serotonin syndrome can develop, since each drug acts on the serotonergic neurotransmitter system. Furthermore, combining levorphanol with anticholinergic medications may heighten the likelihood of urinary retention and severe constipation, potentially progressing to paralytic ileus. Should combined use be required, monitor the patient closely, especially when starting therapy and when doses are being changed, watching for serotonin syndrome as well as for indications of urinary retention or diminished gastric motility. Levorphanol should be stopped if serotonin syndrome is suspected1.
Why it happens (mechanism)
Additive effects on gastric motility; additive serotonergic effects
How to manage this interaction
If you're prescribed both, keep taking them exactly as directed unless your prescriber tells you otherwise. Your care team can manage this by watching you more closely and tailoring your doses.
- Watch for serotonin syndrome: agitation, confusion, sweating, shivering, fast heartbeat, tremor, or muscle twitching, especially when starting or changing a dose. Get medical help promptly if these appear.
- Watch your gut and bladder: report severe constipation, no bowel movement, belly pain and bloating, or trouble urinating.
- Ask your pharmacist about staying hydrated and whether a stool softener or laxative plan makes sense for you.
- Your prescriber may adjust doses or, if needed, stop levorphanol.
Management is individual — confirm any change with your pharmacist or prescriber.
Common questions
Can I take Amitriptyline and Levorphanol together?
Taken together, amitriptyline and levorphanol can add up to cause serotonin syndrome and worsen constipation or urinary retention, so watch for these symptoms and stay in close contact with your care team, especially when starting or changing doses. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Amitriptyline and Levorphanol 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 Levorphanol interaction managed?
If you're prescribed both, keep taking them exactly as directed unless your prescriber tells you otherwise. Your care team can manage this by watching you more closely and tailoring your doses. Watch for serotonin syndrome: agitation, confusion, sweating, shivering, fast heartbeat, tremor, or muscle twitching, especially when starting or changing a dose. Get medical help promptly if these appear.… 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 Levorphanol 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 (1)
- Product Information: levorphanol tartrate oral tablets, levorphanol tartrate oral tablets. Sentynl Therapeutics Inc (per DailyMed), Solana Beach, CA, 2016. DailyMed
Keep reading about Amitriptyline
Keep reading about Levorphanol
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