Quinine 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
Quinine
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.
Both amitriptyline (a medicine often used for depression or nerve pain) and quinine can affect the timing of your heartbeat. Doctors call this the QT interval. When you take them together, their effects can add up and, in rare cases, this can lead to an irregular, dangerous heart rhythm.
Right now this concern is based mostly on how each drug works rather than lots of real-world cases, so try not to worry. The important thing is that your care team can manage this. Please talk with your pharmacist or doctor before taking both, and let them know if you ever feel a fast, pounding, or skipping heartbeat, dizziness, or fainting.
Effect: Additive QT interval prolongation with increased risk of serious ventricular arrhythmia (including torsades de pointes) when amitriptyline and quinine are used together.
Mechanism: Pharmacodynamic (additive), not PK-based. Both agents independently prolong cardiac repolarization. Neither is a relevant prodrug in this context.
- Direction/magnitude: Additive QTc effect; magnitude unquantified.
- Onset: Unspecified.
- Evidence: Theoretical.
- Management: Avoid concomitant use where possible. If unavoidable, obtain baseline and follow-up ECGs, monitor electrolytes (K+, Mg2+), review other QT-prolonging agents, and use lowest effective doses.
What happens
An increased risk of QT interval prolongation
Interaction Deep Dive
The combined use of amitriptyline and quinine should be avoided, as the two may exert additive effects on the QT interval, thereby raising the likelihood of serious cardiovascular effects1.
Why it happens (mechanism)
Additive effects on the QT interval
How to manage this interaction
The documented advice is to avoid taking amitriptyline and quinine together when possible, because their effects on heart rhythm can add up.
- Keep taking both as prescribed for now, and do not stop either one on your own.
- Ask your pharmacist or prescriber whether these two should be used together, or whether an alternative is a better fit for you.
- Your care team may check your heart rhythm (an ECG) and blood levels, and can tailor your treatment and monitoring.
- Get medical help right away for fainting, severe dizziness, or a fast or irregular heartbeat.
Management is individual — confirm any change with your pharmacist or prescriber.
Common questions
Can I take Quinine and Amitriptyline together?
Amitriptyline and quinine can each prolong the QT interval, so combining them may raise the risk of a serious heart rhythm problem; guidance is to avoid using them together, so check with your pharmacist or doctor. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Quinine 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 Quinine and Amitriptyline interaction managed?
The documented advice is to avoid taking amitriptyline and quinine together when possible, because their effects on heart rhythm can add up. Keep taking both as prescribed for now, and do not stop either one on your own. Ask your pharmacist or prescriber whether these two should be used together, or whether an alternative is a better fit for you. Your care team may check your heart rhythm (an ECG)… 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 Quinine 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: QUALAQUIN(R) oral capsules, quinine sulfate oral capsules. AR Scientific, Inc. Philadelphia, PA, 2011. DailyMed
Keep reading about Amitriptyline
Keep reading about Quinine
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Prescription drugs aren't the whole picture — herbal and dietary supplements can interact with them too. From the evidence-graded Natural Medicines database:
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