Amitriptyline and Degarelix: 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
Degarelix
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) and degarelix (Firmagon) 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 an irregular or dangerous heartbeat.
This concern is based on how the drugs work rather than a large number of reported cases, so please don't be alarmed. Keep taking both exactly as prescribed and let your care team know you're on both. They can keep an eye on your heart rhythm and your blood minerals (like potassium and magnesium) and adjust things if needed to keep you safe.
Effect: Additive QT-interval prolongation with increased risk of torsades de pointes. This is a pharmacodynamic (additive), not pharmacokinetic, interaction; neither agent's metabolism is altered.
- Direction: Both amitriptyline (TCA, known QT effect) and degarelix (androgen deprivation via GnRH antagonism can prolong QT) contribute additively.
- Severity/onset: Major; onset unspecified.
- Evidence: Theoretical.
- Management: Avoid combination when possible. Weigh benefit of ADT against risk, especially with congenital long QT, CHF, or electrolyte disturbance. If used together, correct and avoid hypokalemia/hypomagnesemia and consider periodic ECG and electrolyte monitoring.
What happens
Increased risk of QT interval prolongation
Interaction Deep Dive
When degarelix is given together with medications that prolong the QT interval, the effects on the QT interval are additive. The androgen deprivation produced by GnRH agonists and antagonists can itself lengthen the QT interval. In patients who have congenital long QT syndrome, congestive heart failure, or recurrent electrolyte abnormalities, as well as in those receiving drugs recognized to prolong the QT interval, weigh whether the advantages of androgen deprivation therapy such as degarelix outweigh the possible risks3. Where feasible, do not use degarelix at the same time as QT prolonging agents. Should coadministration be necessary, steer clear of drugs that produce electrolyte disturbances (that is, hypokalemia or hypomagnesemia)1, correct any electrolyte abnormalities, and consider periodic monitoring of ECGs and electrolytes3.
Why it happens (mechanism)
Additive QT interval prolongation
How to manage this interaction
The main goal is to protect your heart rhythm while you get the benefit of both medicines.
- Keep taking both as prescribed unless your prescriber tells you otherwise. Do not stop either on your own.
- Your care team may check ECGs and blood electrolytes (potassium and magnesium) from time to time and correct any low levels.
- They will weigh the benefits of degarelix against the risks, especially if you have a heart condition, heart failure, or a history of electrolyte problems.
- Tell your pharmacist or doctor about all your medicines, and report fainting, dizziness, or palpitations right away.
Management is individual — confirm any change with your pharmacist or prescriber.
Literature reports
1 report — tap to read
a) In an analysis of male patients on androgen deprivation therapy (ADT) using individual case safety reports from the international pharmacovigilance database VigiBase, investigators identified 184 cases of acquired long-QT syndrome (aLQTS) and/or torsades de pointes (TdP; 11% fatal cases) and 99 cases of sudden death linked to ADT. The majority of aLQTS/TdP cases (62%) and sudden death cases (88%) associated with ADT arose without concurrent use of other agents recognized to raise TdP risk; nevertheless, use of 1 drug and of 2 or more drugs carrying conditional, possible, or known TdP risk was reported in a portion of aLQTS/TdP (23% or 43%) and sudden death (18% and 22%) events. The agents classified as ADTs were abiraterone, gonadotropin-releasing hormone agonists and antagonists, nonsteroidal androgen receptor inhibitors indicated for prostate cancer, and 5-alpha-reductase inhibitors indicated for androgenic alopecia and prostatism. Among the 10 ADTs assessed, 7 showed a disproportional association (reporting odds ratio, 1.4 to 4.7) with aLQTS, TdP, or sudden death, namely leuprorelin, goserelin, triptorelin, degarelix, bicalutamide, finasteride, and dutasteride. The median patient age was approximately 76 years, and the median time to onset was 170 days (range, 7 to 4884 days) for aLQTS/TdP events and 92 days (range, 0.25 to 4984 days) for sudden death events. Patients were taking ADT chiefly for prostate cancer, with some being treated for prostatism and androgenic alopecia. Most patients were on ADT monotherapy (83%); 17% were receiving ADT combination therapy 2.
Common questions
Can I take Amitriptyline and Degarelix together?
Taking amitriptyline and degarelix together can add up to prolong the QT interval, so your care team may monitor your ECG and electrolytes; keep taking both as prescribed and report any fainting or palpitations. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Amitriptyline and Degarelix 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 Degarelix interaction managed?
The main goal is to protect your heart rhythm while you get the benefit of both medicines. Keep taking both as prescribed unless your prescriber tells you otherwise. Do not stop either on your own. Your care team may check ECGs and blood electrolytes (potassium and magnesium) from time to time and correct any low levels. They will weigh the benefits of degarelix against the risks, especially if yo… 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 Degarelix 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 (3)
- Lyon AR, Lopez-Fernandez T, Couch LS, et al: 2022 ESC guidelines on cardio-oncology developed in collaboration with the European Hematology Association (EHA), the European Society for Therapeutic Radiology and Oncology (ESTRO) and the International Cardio-Oncology Society (IC-OS). Eur Heart J 2022; 43(41):4229-4361.
- Salem JE, Yang T, Moslehi JJ, et al: Androgenic effects on ventricular repolarization: a translational study from the international pharmacovigilance database to iPSC-cardiomyocytes. Circulation 2019; 140(13):1070-1080. PubMed
- Product Information: FIRMAGON(R) subcutaneous injection, degarelix subcutaneous injection. Ferring Pharmaceuticals Inc (per FDA), Parsippany, NJ, 2020. DailyMed
Keep reading about Amitriptyline
Keep reading about Degarelix
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.
Check another combination
Our instant two-drug interaction checker is almost here.
Still have questions about this combination?
Every question gets a real answer from a licensed pharmacist — free, and usually within a day.
Ask the pharmacist