Clofazimine 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
Clofazimine
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 of these medicines can affect your heart's rhythm. Amitriptyline (Elavil), a medicine often used for depression or nerve pain, and clofazimine, an antibiotic, can each slightly slow the way your heart resets between beats. Doctors call this QT prolongation. When you take both together, that effect can add up and, in rare cases, lead to an irregular heartbeat.
The good news is that this is mostly a theoretical concern based on how the drugs work, not something that happens to everyone. Your care team can manage it easily, often by checking your heart with an ECG. If you feel dizzy, faint, or notice a pounding or racing heart, let your doctor know right away.
Mechanism: Additive QT interval prolongation. Both amitriptyline (a TCA with known cardiac conduction effects) and clofazimine independently prolong the QT interval; concurrent use raises the combined risk of QTc prolongation and, rarely, torsades de pointes. Neither is a prodrug relevant here; this is a pharmacodynamic (additive) interaction, not a metabolic one.
- Direction: Additive QT effect (increased risk).
- Severity/Evidence: Major severity, theoretical substantiation.
- Onset: Unspecified.
- Management: Obtain baseline and periodic ECGs; monitor QTc and electrolytes (K+, Mg2+). Avoid additional QT-prolonging agents where possible. Dose may need to be individualized by the care team.
What happens
An increased risk of QT interval prolongation
Interaction Deep Dive
When clofazimine is given together with other drugs that prolong the QT interval, ECG monitoring is advised1.
Why it happens (mechanism)
Additive QT interval prolongation
How to manage this interaction
This interaction is manageable with monitoring. Keep taking both medicines exactly as prescribed unless your doctor tells you otherwise. Here is what your care team typically does:
- Checks your heart rhythm with an ECG, sometimes before and during treatment.
- May check and correct blood minerals like potassium and magnesium.
- May adjust and individualize your doses, or review other medicines you take that could also affect heart rhythm.
What you can do: Tell your pharmacist or prescriber about all your medicines, and report any dizziness, fainting, or a racing or irregular heartbeat promptly.
Management is individual — confirm any change with your pharmacist or prescriber.
Common questions
Can I take Clofazimine and Amitriptyline together?
Taking amitriptyline and clofazimine together can add up to a higher risk of QT prolongation, so your care team may check your heart with ECGs. Keep taking both as prescribed and report any fainting or irregular heartbeat. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Clofazimine 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 Clofazimine and Amitriptyline interaction managed?
This interaction is manageable with monitoring. Keep taking both medicines exactly as prescribed unless your doctor tells you otherwise. Here is what your care team typically does: Checks your heart rhythm with an ECG, sometimes before and during treatment. May check and correct blood minerals like potassium and magnesium. May adjust and individualize your doses, or review other medicines you take… 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 Clofazimine 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: LAMPRENE(R) oral capsules, clofazimine oral capsules. Novartis Pharmaceuticals Corporation (per FDA), East Hanover, NJ, 2019.
Keep reading about Amitriptyline
Keep reading about Clofazimine
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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