Amitriptyline and Trazodone: 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
Trazodone
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.
Amitriptyline (Elavil) and trazodone both raise a brain chemical called serotonin, and both can affect your heart's rhythm. Taking them together can add these effects up. In rare cases, too much serotonin can cause a problem called serotonin syndrome, with symptoms like agitation, a fast heartbeat, sweating, shaking, or confusion. Both drugs can also stretch out part of your heartbeat (the QT interval).
This is a theoretical concern, not something proven to happen in everyone, so please don't panic. Keep taking both exactly as prescribed and let your pharmacist or doctor know you're on both, so they can watch you closely and keep you safe.
Interaction: Additive serotonergic effect and additive QT prolongation from combining amitriptyline (a TCA) with trazodone. Both are serotonergic and both prolong the QT interval; the risk is pharmacodynamic, not a CYP metabolism issue. Neither concern is prodrug-dependent.
- Effect/direction: Increased risk of serotonin syndrome and additive QTc prolongation.
- Evidence: Theoretical; severity rated major.
- Onset: Unspecified; vigilance highest at initiation/dose changes.
- Management: Avoid concurrent use where possible. If combined, counsel on serotonin syndrome symptoms, monitor mental status, autonomic and neuromuscular signs, and consider ECG monitoring, especially with other QT risk factors or electrolyte abnormalities. Discontinue and give supportive care if symptoms emerge.
What happens
Increased risk of serotonin syndrome and an increased risk of QT interval prolongation
Interaction Deep Dive
As a serotonergic agent, traZODone is recognized for its ability to lengthen the QT interval. It should not be combined with another serotonergic drug that also prolongs the QT interval, because taking them together can produce additive serotonin syndrome, cardiac arrhythmia, or both effects. The resulting signs and symptoms can encompass altered mental status (for example, agitation, hallucinations, delirium, or coma), autonomic instability (for example, tachycardia, labile blood pressure, dizziness, diaphoresis, flushing, or hyperthermia), neuromuscular manifestations (for example, tremor, rigidity, myoclonus, hyperreflexia, or incoordination), seizures, and gastrointestinal complaints such as nausea, vomiting, or diarrhea. Every patient receiving traZODone should be watched for serotonin syndrome, particularly at the start of therapy. When the combination cannot be avoided, inform patients about the heightened risk of serotonin syndrome and observe them for symptoms. Should any symptoms develop, stop traZODone and the accompanying serotonergic agent right away and begin supportive care12.
Why it happens (mechanism)
Additive serotonergic effects; additive QT interval prolongation
How to manage this interaction
Your care team may prefer to avoid using these two together when possible. If both are needed, they can manage it safely by watching you more closely, especially when either drug is started or a dose is changed.
- Keep taking both as prescribed unless your prescriber tells you otherwise.
- Your team may monitor you more closely and could check your heart rhythm with an ECG.
- Learn the warning signs: agitation, confusion, fast heartbeat, sweating, tremor, muscle stiffness, fever, or nausea and vomiting.
Contact your pharmacist or prescriber if you have questions, and seek care right away if these symptoms appear.
Management is individual — confirm any change with your pharmacist or prescriber.
Common questions
Can I take Amitriptyline and Trazodone together?
Combining amitriptyline and trazodone can add up serotonin and heart-rhythm (QT) effects, so this combo is often avoided; if you take both, stay alert for serotonin syndrome symptoms and let your care team monitor you. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Amitriptyline and Trazodone 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 Trazodone interaction managed?
Your care team may prefer to avoid using these two together when possible. If both are needed, they can manage it safely by watching you more closely, especially when either drug is started or a dose is changed. Keep taking both as prescribed unless your prescriber tells you otherwise. Your team may monitor you more closely and could check your heart rhythm with an ECG. Learn the warning signs: ag… 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 Trazodone 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)
Keep reading about Amitriptyline
Keep reading about Trazodone
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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