Formoterol 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
Formoterol
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) is an antidepressant, and formoterol (Perforomist) is an inhaler that opens up your airways. On their own, each one can slightly stretch out a part of your heartbeat called the QT interval. When you take them together, that effect can add up, and formoterol's effects on your heart may get a little stronger.
This is a theoretical concern, meaning it's based on how the drugs work rather than lots of real-world cases. But because it involves the heart, it's worth taking seriously. The good news: your care team can manage this safely by keeping a closer eye on you. Please don't stop either medicine on your own, just talk with your doctor or pharmacist.
Effect: Additive QTc prolongation and potentiation of formoterol's cardiovascular effects (increased risk of ventricular arrhythmias).
Mechanism: Both agents independently prolong the QTc interval; combined use is additive. Amitriptyline (a TCA) may also potentiate the sympathomimetic cardiovascular effects of the beta-2 agonist formoterol. Neither is a prodrug relevant to this PD interaction.
Evidence/onset: Theoretical; onset unspecified. Severity rated major.
- Assess baseline and periodic ECG for QTc, especially with additional risk factors.
- Correct electrolytes (K+, Mg2+).
- Monitor for palpitations, syncope, tachyarrhythmia.
- Consider alternative agents if QTc risk is high; doses may need individualization by the care team.
What happens
Increased risk of QT interval prolongation and an increased risk of cardiovascular adverse effects
Interaction Deep Dive
When formoterol is used at the same time as TCAs that likewise lengthen the QTc interval, these agents can enhance formoterol's cardiovascular effects, so extreme caution together with close monitoring for adverse cardiovascular events is warranted. Furthermore, giving formoterol alongside other agents that prolong the QTc interval may raise the likelihood of ventricular arrhythmias1.
Why it happens (mechanism)
Additive QT interval prolongation; potentiation of cardiovascular effects of formoterol
How to manage this interaction
The key here is close observation, since this is a theoretical but potentially serious heart-rhythm concern.
- Keep taking both medicines as prescribed unless your doctor tells you otherwise.
- Your care team may watch you more closely, which can include heart tracing (ECG) and checking your blood minerals like potassium and magnesium.
- Tell your prescriber about any palpitations, fainting, dizziness, or a racing or irregular heartbeat right away.
- Mention any other medicines you take, since some also affect heart rhythm.
Ask your pharmacist or doctor whether this combination is right for you, or if an alternative might be a better fit for your situation.
Management is individual — confirm any change with your pharmacist or prescriber.
Common questions
Can I take Formoterol and Amitriptyline together?
Taking amitriptyline and formoterol together can add up to affect your heart's rhythm, so keep taking both as prescribed and let your care team monitor you and watch for palpitations, dizziness, or fainting. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Formoterol 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 Formoterol and Amitriptyline interaction managed?
The key here is close observation, since this is a theoretical but potentially serious heart-rhythm concern. Keep taking both medicines as prescribed unless your doctor tells you otherwise. Your care team may watch you more closely, which can include heart tracing (ECG) and checking your blood minerals like potassium and magnesium. Tell your prescriber about any palpitations, fainting, dizziness,… 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 Formoterol 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: SYMBICORT AEROSPHERE(R) oral inhalation aerosol, budesonide formoterol fumarate oral inhalation aerosol. AstraZeneca Pharmaceuticals LP (per FDA), Wilmington, DE, 2023.
Keep reading about Amitriptyline
Keep reading about Formoterol
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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