Amitriptyline and Mobocertinib: 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
Mobocertinib
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 electrical rhythm in the same way. Amitriptyline (for mood or nerve pain) and mobocertinib (a cancer medicine) can each stretch out a part of your heartbeat called the QT interval. When you take them together, that effect can add up, which in rare cases can lead to a dangerous irregular heartbeat.
The good news is that this is a known, manageable concern. Your care team can watch your heart with ECGs and decide the safest plan for you. Please don't stop or change either medicine on your own. Talk with your doctor or pharmacist, and let them know if you feel dizzy, faint, or notice a fluttering heartbeat.
Additive QT prolongation. Both amitriptyline (a TCA with known QTc-prolonging effect) and mobocertinib (an EGFR TKI with a labeled QTc-prolongation risk) can prolong the QTc interval; concurrent use raises the risk of torsades de pointes.
- Mechanism: additive pharmacodynamic QTc prolongation (not a metabolic/prodrug interaction).
- Direction: increased combined QTc effect.
- Evidence: theoretical; severity rated major.
- Management: avoid concomitant use if possible. If unavoidable, obtain baseline and serial ECGs, correct electrolytes (K+, Mg2+), and review other QT-prolonging agents. Monitor for syncope, palpitations, and arrhythmia.
What happens
An increased risk of QT interval prolongation
Interaction Deep Dive
When mobocertinib is given together with agents recognized to lengthen the corrected QT (QTc) interval, the likelihood of QTc interval prolongation may rise, including torsades de pointes, a condition that can be fatal. The simultaneous use of mobocertinib with other drugs known to prolong the QTc interval should be avoided. In cases where such concurrent use cannot be avoided, perform more frequent ECG monitoring of the QTc interval1.
Why it happens (mechanism)
Additive QT interval prolongation
How to manage this interaction
Your care team can manage this by keeping a close eye on your heart rhythm.
- Keep taking both medicines as prescribed unless your doctor tells you otherwise.
- Your team may avoid using them together when possible, or if both are needed, they may check your heart with ECGs more often.
- They may also check your potassium and magnesium levels, since low levels add to the risk.
- Tell your pharmacist or doctor about all your medicines, since other drugs can add to this heart effect.
Call your doctor right away if you feel faint, dizzy, or notice a racing or fluttering heartbeat.
Management is individual — confirm any change with your pharmacist or prescriber.
Common questions
Can I take Amitriptyline and Mobocertinib together?
Amitriptyline and mobocertinib can both prolong the QT interval, and combining them may increase the risk of a dangerous heart rhythm. Don't stop either on your own; ask your care team, who can avoid the combination or monitor your heart with ECGs. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Amitriptyline and Mobocertinib 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 Mobocertinib interaction managed?
Your care team can manage this by keeping a close eye on your heart rhythm. Keep taking both medicines as prescribed unless your doctor tells you otherwise. Your team may avoid using them together when possible, or if both are needed, they may check your heart with ECGs more often. They may also check your potassium and magnesium levels, since low levels add to the risk. Tell your pharmacist or do… 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 Mobocertinib 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: EXKIVITY(TM) oral capsules, mobocertinib oral capsules. Takeda Pharmaceuticals America Inc (per FDA), Lexington, MA, 2021.
Keep reading about Amitriptyline
Keep reading about Mobocertinib
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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