Levomethadyl 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
Levomethadyl
No brand names on record
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.
These two medicines should not be taken together. Both amitriptyline (Elavil), an older antidepressant, and levomethadyl can affect the heart's rhythm in the same way. They can each stretch out a part of your heartbeat called the QT interval. When two medicines do this at the same time, the effect can add up and, in rare cases, lead to a dangerous heart rhythm.
The good news is that this is easy to avoid. Your doctor and pharmacist keep an eye out for combinations like this. If you have been prescribed both, don't stop anything on your own, just reach out to your care team and let them find a safer option for you.
Contraindicated combination due to additive risk of QT prolongation and torsades de pointes.
- Mechanism: Pharmacodynamic (additive), not pharmacokinetic. Both agents independently prolong the QT interval; neither is a relevant prodrug here.
- Direction: Additive cardiotoxicity (QT prolongation, TdP, cardiac arrest).
- Onset: Delayed.
- Evidence: Theoretical; based on known QT liability of each agent.
- Management: Avoid coadministration. Levomethadyl is contraindicated with amitriptyline. If both are somehow required, use an alternative agent; do not co-prescribe.
What happens
An increased risk of cardiotoxicity (QT prolongation, torsades de pointes, cardiac arrest)
Interaction Deep Dive
Levomethadyl must not be combined with any medication recognized as having the capacity to lengthen the QT interval. Pharmacodynamic interactions may arise when levomethadyl is given alongside agents that are potentially arrhythmogenic and prolong the QT interval, for example amitriptyline1.
Why it happens (mechanism)
Unknown
How to manage this interaction
The main step here is avoiding the combination. Because both drugs can prolong the QT interval, the care team's usual approach is to not use them together and to choose a safer alternative for one of them.
- Keep taking your medicines as prescribed until you speak with your care team, do not stop on your own.
- Tell your pharmacist and prescriber that you have been given both so they can review your regimen.
- Ask whether one medicine can be swapped for an alternative.
- Report any fainting, palpitations, or dizziness right away.
Management is individual — confirm any change with your pharmacist or prescriber.
Common questions
Can I take Levomethadyl and Amitriptyline together?
Amitriptyline and levomethadyl should not be used together because both can prolong the QT interval and raise the risk of a serious heart rhythm problem. Contact your prescriber or pharmacist so one medicine can be changed, but do not stop anything on your own. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Levomethadyl and Amitriptyline interaction?
It is rated contraindicated. These should generally not be used together.
How quickly could this interaction happen?
The documented onset is "delayed". Effects tend to build up gradually over days to weeks.
How is the Levomethadyl and Amitriptyline interaction managed?
The main step here is avoiding the combination. Because both drugs can prolong the QT interval, the care team's usual approach is to not use them together and to choose a safer alternative for one of them. Keep taking your medicines as prescribed until you speak with your care team, do not stop on your own. Tell your pharmacist and prescriber that you have been given both so they can review your r… 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 Levomethadyl 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 (1)
- Product Information: Orlaam(R), levomethadyl. Roxane Laboratories, Inc. Columbus, OH, 2001.
Keep reading about Amitriptyline
Keep reading about Levomethadyl
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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