Lisdexamfetamine 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
Lisdexamfetamine
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 Vyvanse (lisdexamfetamine) can both raise the activity of a brain chemical called serotonin. When two drugs do this together, there is a small chance of building up too much serotonin, which can cause a reaction called serotonin syndrome. Signs can include feeling agitated or shaky, a fast heartbeat, sweating, a high temperature, or muscle twitching.
The good news is this is considered a theoretical risk, and many people take these two safely together. Your care team can manage it by starting low and watching how you respond. If you notice those symptoms, contact your doctor right away, but don't stop either medicine on your own.
Effect: Additive serotonergic activity may increase the risk of serotonin syndrome. Amitriptyline (a TCA with serotonin reuptake inhibition) plus lisdexamfetamine (a prodrug hydrolyzed to d-amphetamine, which promotes monoamine release) act on overlapping serotonergic pathways. Amphetamine CNS exposure and cardiovascular effects may also be potentiated.
- Direction: Increased serotonergic and sympathomimetic effect (PD interaction)
- Severity: Major; evidence: theoretical; onset: unspecified
- Management: If combination is required, initiate at lower doses and monitor closely, especially during initiation and titration. Watch for hyperthermia, autonomic instability, clonus, agitation. Discontinue both agents if serotonin syndrome is suspected.
What happens
An increased risk of serotonin syndrome
Interaction Deep Dive
When an amphetamine is given together with another serotonergic drug, serotonin syndrome may develop, since each of these agents acts on the serotonergic neurotransmitter system12. Beyond this, prolonged elevations in brain d-amphetamine levels can occur, and cardiovascular effects may be intensified1. Should the combination of an amphetamine and such an agent be clinically necessary, therapy should begin at reduced doses, with close observation of patients, particularly when treatment is started and when the dose is being adjusted. Both medications should be stopped if serotonin syndrome is suspected32.
Why it happens (mechanism)
Additive serotonergic effects
How to manage this interaction
Your care team can manage this combination safely with a few precautions:
- Keep taking both as prescribed unless your prescriber tells you otherwise.
- Doses may be started low and individualized, with closer monitoring during the first weeks and after any dose change.
- Learn the warning signs of serotonin syndrome: agitation, confusion, fast heartbeat, high fever, heavy sweating, shivering, muscle twitching, or shaking.
- Contact your prescriber or pharmacist if you notice these symptoms, and seek urgent care if they are severe.
Bring up any new medicines, supplements, or worsening symptoms with your pharmacist or doctor so they can keep an eye on you.
Management is individual — confirm any change with your pharmacist or prescriber.
Common questions
Can I take Lisdexamfetamine and Amitriptyline together?
Taking amitriptyline with Vyvanse carries a theoretical risk of serotonin syndrome, so watch for symptoms like agitation, fever, or a racing heart. Keep taking both as prescribed and let your care team know of any warning signs. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Lisdexamfetamine 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 Lisdexamfetamine and Amitriptyline interaction managed?
Your care team can manage this combination safely with a few precautions: Keep taking both as prescribed unless your prescriber tells you otherwise. Doses may be started low and individualized, with closer monitoring during the first weeks and after any dose change. Learn the warning signs of serotonin syndrome: agitation, confusion, fast heartbeat, high fever, heavy sweating, shivering, muscle tw… 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 Lisdexamfetamine 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 (3)
- Product Information: VYVANSE(R) oral capsules, oral chewable tablets, lisdexamfetamine dimesylate oral capsules, oral chewable tablets. Shire US Inc (per DailyMed), Lexington, MA, 2018. DailyMed
- Product Information: FETZIMA(R) oral extended-release capsules, levomilnacipran oral extended-release capsules. AbbVie Inc (per FDA), North Chicago, IL, 2023. DailyMed
- Product Information: ADDERALL(R) oral tablets, dextroamphetamine saccharate amphetamine aspartate dextroamphetamine sulfate amphetamine sulfate oral tablets. Teva Select Brands (per FDA), Horsham, PA, 2017. DailyMed
Keep reading about Amitriptyline
Keep reading about Lisdexamfetamine
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.
Check another combination
Our instant two-drug interaction checker is almost here.
Still have questions about this combination?
Every question gets a real answer from a licensed pharmacist — free, and usually within a day.
Ask the pharmacist