Buprenorphine and Quizartinib: 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
Buprenorphine
Quizartinib
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. Buprenorphine (for pain or opioid treatment) and quizartinib (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 could lead to an abnormal heartbeat.
The good news is that this is a known and manageable risk. Your care team can keep an eye on things with heart tracings (EKGs) and blood tests, and adjust your treatment if needed. Please don't stop either medicine on your own. Just talk with your doctor or pharmacist so they can watch you closely.
Mechanism: Additive QT interval prolongation. Both agents independently prolong the QT interval; neither is a prodrug and the concern is pharmacodynamic, not metabolic.
Direction/magnitude: Combined use increases the incidence and degree of QTc prolongation and torsades risk. Evidence is theoretical but severity is rated major; onset unspecified.
Management:
- Obtain baseline and periodic ECGs; monitor QTc.
- Check and correct serum electrolytes (K+, Mg2+, Ca2+).
- Reduce dose, interrupt, or discontinue quizartinib per its labeling if QTc prolongs.
- Assess other QT-prolonging agents and bradycardia risk.
What happens
An increased risk of QT interval prolongation
Interaction Deep Dive
Giving quizartinib together with additional agents known to lengthen the QT interval can add to the risk of QT prolongation. Track electrocardiograms and serum electrolyte concentrations. As warranted, lower the quizartinib dose, pause therapy, or stop it permanently1.
Why it happens (mechanism)
Additive QT interval prolongation
How to manage this interaction
Keep taking both medicines as prescribed unless your care team tells you otherwise. Because these drugs can add to each other's effect on heart rhythm, your team has clear ways to manage this.
- Expect heart tracings (EKGs) before and during treatment to watch your QT interval.
- Expect blood tests to check electrolytes like potassium and magnesium, which are corrected if low.
- Your quizartinib dose may be adjusted, paused, or changed by your oncology team based on your EKG results.
Tell your pharmacist or doctor if you feel faint, dizzy, or notice a pounding or irregular heartbeat, and mention any other medicines you take.
Management is individual — confirm any change with your pharmacist or prescriber.
Common questions
Can I take Buprenorphine and Quizartinib together?
Taking buprenorphine and quizartinib together can add to the risk of QT prolongation (a heart rhythm effect), so your team will monitor EKGs and electrolytes and adjust the quizartinib dose if needed. Keep both medicines going as prescribed and report any dizziness, fainting, or irregular heartbeat. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Buprenorphine and Quizartinib 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 Buprenorphine and Quizartinib interaction managed?
Keep taking both medicines as prescribed unless your care team tells you otherwise. Because these drugs can add to each other's effect on heart rhythm, your team has clear ways to manage this. Expect heart tracings (EKGs) before and during treatment to watch your QT interval. Expect blood tests to check electrolytes like potassium and magnesium, which are corrected if low. Your quizartinib dose ma… 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.
Questions for your pharmacist
- Does my dose of Buprenorphine or Quizartinib 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: VANFLYTA® oral tablets, quizartinib oral tablets. Daiichi Sankyo, Basking Ridge, NJ, 2026. DailyMed
Keep reading about Buprenorphine
Keep reading about Quizartinib
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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