Amitriptyline and Hydromorphone: 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
Hydromorphone
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.
Taking Amitriptyline (Elavil) and Hydromorphone (Dilaudid) together needs a little extra care. Both medicines can affect a brain chemical called serotonin. When they are combined, there is a small chance of a reaction called serotonin syndrome, which can cause agitation, a fast heartbeat, sweating, shaking, or muscle stiffness.
These two drugs can also both slow down your gut and bladder. That may lead to bad constipation or trouble urinating, and in rare cases the bowel can nearly stop moving. This warning is based mostly on theory, so try not to worry. Your care team can manage this safely by watching you closely and adjusting doses. Call your doctor or pharmacist if you feel any of these symptoms.
Additive pharmacodynamic interaction. Amitriptyline (serotonergic and strongly anticholinergic TCA) plus hydromorphone (opioid with serotonergic activity) can produce overlapping effects.
- Serotonin syndrome: additive serotonergic activity increases risk, especially at initiation and dose titration.
- GI/GU: additive reduction in gastric motility and anticholinergic burden raises risk of severe constipation, urinary retention, and potentially paralytic ileus.
Direction: additive PD effects, not a PK/enzyme change. Evidence: theoretical. Severity: major. Management: monitor for autonomic instability, neuromuscular changes, altered mental status, bowel/bladder function. Discontinue hydromorphone if serotonin syndrome is suspected. Doses may be individualized by the care team.
What happens
Increased risk of paralytic ileus and an increased risk of serotonin syndrome
Interaction Deep Dive
Serotonin syndrome has occurred when opioids like HYDROmorphone are taken together with serotonergic agents. Combining HYDROmorphone with anticholinergic drugs may also heighten the likelihood of urinary retention and severe constipation, potentially progressing to paralytic ileus. When such combinations are necessary, monitor the patient closely, especially at the start of therapy and when doses are being changed, watching for serotonin syndrome as well as any indications of urinary retention or diminished gastric motility. HYDROmorphone should be stopped if serotonin syndrome is suspected. Instances of serotonin syndrome, a condition that can be life-threatening, have been documented with the combined use of opioids and serotonergic drugs123.
Why it happens (mechanism)
Additive effects on gastric motility; additive serotonergic effects
How to manage this interaction
You can usually take both when your care team decides you need them. The plan is watchful use, not automatic avoidance.
- Keep taking both exactly as prescribed unless your prescriber tells you otherwise.
- Your team may watch you more closely, especially when either drug is started or a dose is changed, and doses may be adjusted and individualized.
- Watch for constipation, trouble passing urine, or belly pain and bloating.
- Get urgent help for agitation, confusion, fever, sweating, shivering, fast heartbeat, or muscle twitching or stiffness.
Raise any of these symptoms with your pharmacist or prescriber promptly.
Management is individual — confirm any change with your pharmacist or prescriber.
Literature reports
1 report — tap to read
Common questions
Can I take Amitriptyline and Hydromorphone together?
Combining amitriptyline and hydromorphone can add up to raise the risk of serotonin syndrome and of severe constipation or urinary retention (possibly paralytic ileus), so use both only under close monitoring and report warning symptoms right away. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Amitriptyline and Hydromorphone 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 Hydromorphone interaction managed?
You can usually take both when your care team decides you need them. The plan is watchful use, not automatic avoidance. Keep taking both exactly as prescribed unless your prescriber tells you otherwise. Your team may watch you more closely, especially when either drug is started or a dose is changed, and doses may be adjusted and individualized. Watch for constipation, trouble passing urine, or be… 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 Hydromorphone 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: EXALGO(R) oral extended-release tablets, hydromorphone HCl oral extended-release tablets. SpecGx LLC (per FDA), Webster Groves, MO, 2019. DailyMed
- Product Information: DILAUDID(R) intravenous injection, intramuscular injection, subcutaneous injection, hydromorphone HCl intravenous injection, intramuscular injection, subcutaneous injection. Fresenius Kabi. (per FDA), Lake Zurich, IL, 2023. DailyMed
- Product Information: DILAUDID(R) oral tablets, oral solution, hydromorphone HCl oral tablets, oral solution. Rhodes Pharmaceuticals LP (per FDA), Wilson, NC, 2023. DailyMed
Keep reading about Amitriptyline
Keep reading about Hydromorphone
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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