Amitriptyline and Histrelin: 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
Histrelin
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.
Here's what's going on. Both of these medicines can affect the timing of your heartbeat, something doctors call the QT interval. Amitriptyline (Elavil) is a tricyclic antidepressant that can stretch out this interval, and histrelin (Supprelin), through its effect on hormones, may do the same. When you take them together, those small effects can add up.
For most people this is a low, mainly theoretical concern, but a longer QT interval can occasionally lead to an abnormal heart rhythm. The good news is your care team can manage this easily by checking an EKG and your blood levels (like potassium and magnesium) and keeping an eye on things. Please keep taking both as prescribed and bring this up at your next visit.
Effect: Additive QT interval prolongation. Amitriptyline is a known QT-prolonging tricyclic antidepressant; histrelin, a GnRH agonist causing androgen deprivation, may also prolong QT. Neither is a prodrug relevant here; this is a pharmacodynamic (additive), not pharmacokinetic, interaction.
- Direction/magnitude: Additive QTc effect; magnitude not quantified.
- Onset: Unspecified.
- Evidence: Theoretical, severity rated major.
- Management: Assess benefit/risk, especially with congenital long QT, CHF, or electrolyte disturbances. Avoid concurrent use when possible. If used, correct and avoid hypokalemia/hypomagnesemia and consider periodic ECG and electrolyte monitoring.
What happens
Increased risk of QT interval prolongation
Interaction Deep Dive
When histrelin 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 lengthen the QT interval. In patients who have congenital long QT syndrome, congestive heart failure, or recurrent electrolyte disturbances, as well as in those receiving drugs recognized to prolong the QT interval, weigh whether the advantages of androgen deprivation therapy such as histrelin justify the potential risks3. Where feasible, do not use histrelin at the same time as QT prolonging agents. Should coadministration be necessary, refrain from using drugs that provoke electrolyte disturbances (that is, hypokalemia or hypomagnesemia)1, correct any electrolyte abnormalities, and consider periodic monitoring of ECGs along with electrolytes3.
Why it happens (mechanism)
Additive QT interval prolongation
How to manage this interaction
Keep taking both medicines as prescribed unless your prescriber tells you otherwise. Because both can lengthen the QT interval, your care team may take some sensible precautions.
- They may check an EKG and blood electrolytes (potassium and magnesium) before and during treatment.
- They will correct any low potassium or magnesium, since these raise QT risk.
- They will weigh whether both drugs are truly needed, especially if you have a heart-rhythm condition, heart failure, or frequent electrolyte problems.
Tell your pharmacist or doctor if you feel faint, dizzy, or have a fluttering or racing heartbeat, and share your full medication and heart history.
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 VigiBase, the international pharmacovigilance database, investigators identified 184 cases of acquired long-QT syndrome (aLQTS) and/or torsades de pointes (TdP; 11% of which were fatal) 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 known to raise TdP risk; nevertheless, use of 1 drug and of 2 or more drugs carrying conditional, possible, or known TdP risk was documented in some aLQTS/TdP events (23% or 43%) and in some sudden death events (18% and 22%). The agents regarded as ADTs included 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 treated for prostatism and androgenic alopecia. Most patients were on ADT monotherapy (83%), while 17% were receiving ADT combination therapy 2.
Common questions
Can I take Amitriptyline and Histrelin together?
Both amitriptyline and histrelin can prolong the QT interval, so together the effect may add up; keep taking both as prescribed and let your care team monitor your EKG and electrolytes. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Amitriptyline and Histrelin 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 Histrelin interaction managed?
Keep taking both medicines as prescribed unless your prescriber tells you otherwise. Because both can lengthen the QT interval, your care team may take some sensible precautions. They may check an EKG and blood electrolytes (potassium and magnesium) before and during treatment. They will correct any low potassium or magnesium, since these raise QT risk. They will weigh whether both drugs are truly… 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 Histrelin 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: VANTAS® subcutaneous implant, histrelin acetate subcutaneous implant. Endo Pharmaceuticals Solutions Inc, Malvern, PA, 2026. DailyMed
Keep reading about Amitriptyline
Keep reading about Histrelin
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