Ciprofloxacin and Relugolix: 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
Ciprofloxacin
No brand names on recordRelugolix
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.
You've been prescribed two medicines that can each affect your heart's electrical rhythm. Ciprofloxacin is an antibiotic, and relugolix (Orgovyx) is used to lower testosterone for prostate cancer. Both can slightly stretch out a part of the heartbeat called the QT interval. When you take them together, that effect can add up, which in rare cases can lead to an irregular heartbeat.
The good news is this is a well-known, manageable concern. Your care team can check your heart rhythm (an ECG) and your electrolyte levels like potassium and magnesium. Please keep taking both exactly as prescribed, and let your pharmacist or doctor know you're on both so they can watch out for you.
Mechanism: Additive QT prolongation. Ciprofloxacin has known QT-prolonging potential, and androgen deprivation from relugolix may also prolong the QT interval. This is a pharmacodynamic interaction, not a metabolic one; neither agent's clearance is the issue.
- Direction/effect: Increased risk of QT prolongation and torsades de pointes.
- Evidence: Theoretical; severity rated major.
- Higher-risk patients: Congenital long QT, CHF, bradyarrhythmia, hypokalemia/hypomagnesemia.
- Management: Avoid concomitant use where possible. If required, correct and maintain electrolytes, avoid other electrolyte-depleting drugs, and consider periodic ECG and electrolyte monitoring.
What happens
Increased risk of QT interval prolongation
Interaction Deep Dive
When relugolix is given together with medications that prolong the QT interval, the effects on 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 disturbances, as well as those receiving drugs recognized for prolonging the QT interval, weigh whether the advantages of androgen deprivation therapy such as relugolix are greater than the possible hazards 1. Where feasible, do not use relugolix alongside QT prolonging agents. Should combined use be necessary, refrain from drugs that produce electrolyte disturbances (that is, hypokalemia or hypomagnesemia) 2, correct any electrolyte abnormalities, and think about periodic monitoring of ECGs and electrolytes 1.
Why it happens (mechanism)
Additive QT interval prolongation
How to manage this interaction
Both drugs can mildly affect heart rhythm, so your care team manages this thoughtfully rather than by a single set dose change.
- Keep taking both as prescribed unless your prescriber tells you otherwise.
- Your team may check an ECG and electrolytes (potassium and magnesium) before or during treatment.
- They may correct any low electrolytes and avoid other medicines that lower them.
- Where possible, they may choose a different antibiotic for a short-term infection.
Tell your pharmacist or doctor if you feel fainting, dizziness, or a fluttering or pounding heartbeat.
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 treated with 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), along with 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 exposure to other agents recognized as increasing TdP risk; nevertheless, exposure to 1 drug and to 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 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 receiving ADT mainly 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 3.
Common questions
Can I take Ciprofloxacin and Relugolix together?
Ciprofloxacin and relugolix can each prolong the QT interval, and together the effect may add up. Keep taking both as prescribed and let your care team know so they can check your heart rhythm and electrolytes. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Ciprofloxacin and Relugolix 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 Ciprofloxacin and Relugolix interaction managed?
Both drugs can mildly affect heart rhythm, so your care team manages this thoughtfully rather than by a single set dose change. Keep taking both as prescribed unless your prescriber tells you otherwise. Your team may check an ECG and electrolytes (potassium and magnesium) before or during treatment. They may correct any low electrolytes and avoid other medicines that lower them. Where possible, th… 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 Ciprofloxacin or Relugolix 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)
- Product Information: ORGOVYX oral tablets, relugolix oral tablets. Sumitomo Pharma America, Inc (per FDA), Marlborough, MA, 2025. DailyMed
- 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
Keep reading about Ciprofloxacin
Keep reading about Relugolix
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