Pacritinib and Buprenorphine: 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
Pacritinib
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 buprenorphine (a pain and addiction medicine) and pacritinib (Vonjo, used for a bone marrow condition) can affect your heart's electrical rhythm. Each one can slightly stretch out a part of the heartbeat called the QT interval. When you take them together, that effect can add up, which can raise the small chance of an irregular heartbeat.
This is based on how these drugs work rather than lots of real-world reports, so please don't panic. The good news is your care team can manage this. They may check your heart with an EKG, keep an eye on your potassium levels, and adjust things as needed. Don't stop either medicine on your own, just talk with your doctor or pharmacist.
Effect: Additive QTc prolongation, increasing risk of ventricular arrhythmias (including torsades de pointes). Both agents are independently associated with QT prolongation; the interaction is pharmacodynamic (additive), not pharmacokinetic. Neither drug's effect here depends on activation, so the risk is straightforward additive PD.
Evidence: Theoretical. Onset: unspecified. Severity: major.
Management:
- Avoid pacritinib in patients with baseline QTc >480 msec.
- Correct hypokalemia/hypomagnesemia before and during therapy.
- Obtain baseline and periodic ECGs.
- Hold pacritinib if QTc >500 msec or increases >60 msec from baseline; resume per resolution timeline (same dose if resolved within 1 week, reduced dose if longer).
What happens
An increased risk of QT interval prolongation
Interaction Deep Dive
Do not give pacritinib together with any agent recognized to lengthen the QTc interval. Because drugs that extend the QT interval can compound the QTc-prolonging action of pacritinib, combining them raises the likelihood of cardiac arrhythmias. Pacritinib should not be used when a patient's baseline QTc exceeds 480 msec. Should the QT interval lengthen beyond 500 msec or increase by more than 60 msec relative to baseline, withhold pacritinib. When the QTc prolongation returns to 480 msec or less, or to baseline, within 1 week, resume pacritinib at the identical dose. When resolution takes longer than 1 week, resume pacritinib at a lowered dose. In situations where the combination cannot be avoided, correct hypokalemia both before and throughout pacritinib therapy, and address QTc prolongation through interruption of pacritinib and electrolyte management1.
Why it happens (mechanism)
Additive QT interval prolongation
How to manage this interaction
Both drugs can lengthen the QT interval, so your care team's main goal is to protect your heart rhythm.
- Keep taking both as prescribed unless your doctor tells you otherwise.
- Your team may do a baseline EKG and repeat it during treatment.
- They will likely check and correct your potassium and magnesium levels, since low levels add to the risk.
- Your pacritinib dose may be paused and then restarted, and it may be adjusted and individualized based on your EKG results.
Tell your pharmacist or prescriber about any dizziness, fainting, or palpitations, and mention all other medicines you take.
Management is individual — confirm any change with your pharmacist or prescriber.
Common questions
Can I take Pacritinib and Buprenorphine together?
Buprenorphine and pacritinib can both prolong the QT interval, so combining them may add up and raise the risk of a dangerous heart rhythm. Your care team can manage this with EKGs, electrolyte checks, and dose adjustments, so keep taking both as prescribed and report any dizziness, fainting, or palpitations. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Pacritinib and Buprenorphine 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 Pacritinib and Buprenorphine interaction managed?
Both drugs can lengthen the QT interval, so your care team's main goal is to protect your heart rhythm. Keep taking both as prescribed unless your doctor tells you otherwise. Your team may do a baseline EKG and repeat it during treatment. They will likely check and correct your potassium and magnesium levels, since low levels add to the risk. Your pacritinib dose may be paused and then restarted,… 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 Pacritinib or Buprenorphine 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: VONJO(R) oral capsules, pacritinib oral capsules. CTI BioPharma Corp (per FDA), Seattle, WA, 2024. DailyMed
Keep reading about Buprenorphine
Keep reading about Pacritinib
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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