Amitriptyline and Piperaquine: 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
Piperaquine
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.
Amitriptyline (Elavil) and piperaquine are not recommended together. There are two concerns. First, both medicines can affect your heart's electrical rhythm (called the QT interval), and using them together can add up and raise the risk of a dangerous heartbeat. Second, piperaquine can slow down how your body breaks down amitriptyline, so more of it can build up and cause stronger side effects like drowsiness, dry mouth, or a fast heartbeat.
Piperaquine also stays in the body a long time. The good news is your care team can manage this by choosing a safer option or watching you closely. Please talk with your pharmacist or doctor before taking both.
Contraindicated combination. Two overlapping concerns:
- QT prolongation (PD): both agents prolong the QT interval; additive effect increases torsades de pointes risk. Piperaquine's long half-life means recently used QT-prolonging drugs still circulating at dosing time are also contraindicated.
- CYP2C19 inhibition (PK): piperaquine inhibits CYP2C19, a partial metabolic pathway for amitriptyline, potentially raising amitriptyline exposure (AUC/Cmax) and anticholinergic/cardiac effects.
Evidence is theoretical; onset unspecified. Avoid co-administration. Caution when using a CYP2C19 substrate for up to 3 months after piperaquine discontinuation. If unavoidable, ECG/QTc and electrolyte monitoring plus individualized dosing are warranted.
What happens
Increased exposure of CYP2C19 substrates and increased risk of QT interval prolongation
Interaction Deep Dive
Giving piperaquine together with agents that prolong the QT interval can produce additive QT-prolonging effects and is contraindicated. Likewise, recent administration of QT-interval prolonging drugs that could still be present in the circulation when piperaquine is given is contraindicated. Because piperaquine inhibits CYP2C19, co-administering it with a CYP2C19 substrate may raise the exposure of that substrate. Given piperaquine's long half-life, caution is warranted1 when a CYP2C19 substrate is used for as long as 3 months following the end of piperaquine therapy.
Why it happens (mechanism)
Inhibition of CYP2C19-mediated metabolism of this drug by piperaquine; additive QT interval prolongation
How to manage this interaction
This pairing is flagged as one to avoid. Here is what typically happens and what to do:
- Your care team will usually choose an alternative to one of these drugs rather than run them together, because of the combined heart-rhythm (QT) risk.
- Because piperaquine lingers in the body, caution applies for up to 3 months after it is stopped.
- If both are truly needed, your team may monitor you more closely (such as heart tracing and blood tests) and individualize your amitriptyline dose.
Do not stop or change either medicine on your own. Keep taking what you are prescribed and raise this combination with your pharmacist or prescriber right away.
Management is individual — confirm any change with your pharmacist or prescriber.
Common questions
Can I take Amitriptyline and Piperaquine together?
Amitriptyline and piperaquine together are contraindicated because both prolong the QT interval and piperaquine can raise amitriptyline levels; talk with your pharmacist or doctor about a safer option before combining them, and note piperaquine's caution window lasts up to 3 months. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Amitriptyline and Piperaquine interaction?
It is rated contraindicated. These should generally not be used together.
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 Piperaquine interaction managed?
This pairing is flagged as one to avoid. Here is what typically happens and what to do: Your care team will usually choose an alternative to one of these drugs rather than run them together, because of the combined heart-rhythm (QT) risk. Because piperaquine lingers in the body, caution applies for up to 3 months after it is stopped. If both are truly needed, your team may monitor you more closely… 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 Piperaquine 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: Eurartesim oral film-coated tablets, piperaquine tetraphosphate dihydroartemisinin oral film-coated tablets. Sigma-Tau Industrie Farmaceutiche Riunite S.p.A (per EMA), Rome, Italy, 2012.
Keep reading about Amitriptyline
Keep reading about Piperaquine
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