Amitriptyline and Inotuzumab Ozogamicin: 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
Inotuzumab Ozogamicin
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 the timing of your heartbeat. Amitriptyline (Elavil), an older antidepressant, and inotuzumab ozogamicin (Besponsa), a chemotherapy medicine, can each stretch out a part of the heart's rhythm called the QT interval. Taking them together can add up and slightly raise the chance of an irregular heartbeat.
The good news is this is a known, manageable concern. Your care team can keep an eye on it with a heart tracing (EKG) and blood tests, and they may adjust your medicines if needed. Please don't stop either drug on your own. Just talk with your doctor or pharmacist so they can plan the safest approach for you.
Effect: Additive QT-interval prolongation from concurrent use of amitriptyline (a TCA with known QT liability) and inotuzumab ozogamicin, increasing arrhythmia risk (including torsades).
Mechanism: Pharmacodynamic additive effect on cardiac repolarization; not a PK/CYP interaction. Neither is a prodrug here.
Evidence: Theoretical; severity major; onset unspecified.
- Prefer a non-QT-prolonging alternative to amitriptyline during inotuzumab therapy.
- If concurrent use is unavoidable, obtain baseline ECG and electrolytes (K+, Mg2+, Ca2+), repeat after initiation, and monitor as clinically indicated.
- Correct electrolyte abnormalities; review other QT-prolonging agents.
What happens
Increased risk of QT-interval prolongation
Interaction Deep Dive
Taking inotuzumab ozogamicin together with medications that prolong the QT interval raises the likelihood of QT prolongation. While a patient is receiving inotuzumab ozogamicin, it is advised to either stop such medications or substitute alternatives that do not affect the QT interval. If it is not possible to avoid using drugs recognized to prolong the QT interval, obtain electrolyte levels and an electrocardiogram before starting therapy, following initiation of the QT-prolonging drug, and as clinically warranted throughout the course of treatment1.
Why it happens (mechanism)
Additive QT-interval prolongation
How to manage this interaction
Keep taking both medicines exactly as prescribed unless your care team tells you otherwise. This interaction is manageable with the right precautions.
Your team may:
- Consider whether a different antidepressant that does not affect the QT interval would work for you.
- Check a heart tracing (EKG) and blood electrolyte levels before starting, after starting, and during treatment.
- Correct any low potassium, magnesium, or calcium.
What you can do: Ask your pharmacist or prescriber to review all your medicines. Report any fainting, dizziness, or palpitations right away.
Management is individual — confirm any change with your pharmacist or prescriber.
Common questions
Can I take Amitriptyline and Inotuzumab Ozogamicin together?
Amitriptyline and inotuzumab can both prolong the QT interval, so together they may raise the risk of an irregular heartbeat. Your care team can manage this with an EKG, electrolyte checks, or by choosing a safer alternative, so talk with them rather than changing anything yourself. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Amitriptyline and Inotuzumab Ozogamicin 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 Amitriptyline and Inotuzumab Ozogamicin interaction managed?
Keep taking both medicines exactly as prescribed unless your care team tells you otherwise. This interaction is manageable with the right precautions. Your team may: Consider whether a different antidepressant that does not affect the QT interval would work for you. Check a heart tracing (EKG) and blood electrolyte levels before starting, after starting, and during treatment. Correct any low potas… 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 Inotuzumab Ozogamicin 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: BESPONSA(TM) intravenous injection, inotuzumab ozogamicin intravenous injection. Pfizer Inc (per FDA), Philadelphia, PA, 2017. DailyMed
Keep reading about Amitriptyline
Keep reading about Inotuzumab Ozogamicin
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