Palbociclib 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
Palbociclib
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're taking two medicines that can interact. Palbociclib (Ibrance) slows down a liver enzyme that normally breaks down buprenorphine. Because buprenorphine gets cleared more slowly, more of it can build up in your body. That can make the opioid effects stronger and last longer, so you might feel extra sleepy, dizzy, or short of breath, and in serious cases your breathing could slow down too much.
The good news is your care team can manage this. Please don't stop or change either medicine on your own. Let your pharmacist or doctor know you take both so they can adjust your buprenorphine dose if needed and watch you more closely.
Effect: Palbociclib is a moderate CYP3A4 inhibitor; it reduces CYP3A4-mediated metabolism of buprenorphine, increasing buprenorphine exposure (AUC/Cmax) and the risk of dose-related opioid toxicity (sedation, respiratory depression).
- Direction: Increased buprenorphine effect (buprenorphine is the affected substrate; not a prodrug requiring activation here).
- Evidence/onset: Probable; onset unspecified. Severity major.
- Management: If starting palbociclib, consider reducing the buprenorphine dose to stable effect and monitor closely for sedation/respiratory depression. On palbociclib discontinuation, anticipate reduced exposure and monitor for withdrawal, adjusting dose upward as needed. Use formulations allowing precise titration when adjustment is required.
What happens
Increased buprenorphine exposure and an increased risk of buprenorphine-related adverse events
Interaction Deep Dive
Combining buprenorphine with a CYP3A4 inhibitor can raise buprenorphine plasma concentrations, which may lead to extended opioid effects such as respiratory depression. When a patient on buprenorphine must also take a CYP3A4 inhibitor, one option is to lower the buprenorphine dose until drug effects stabilize, while frequently watching for sedation and respiratory depression. Conversely, if a CYP3A4 inhibitor is stopped in a patient who continues buprenorphine, an increase in the buprenorphine dose may be warranted until stable effects are reached, along with monitoring for indications of opioid withdrawal2. Should dose adjustment prove impossible once the CYP3A4 inhibitor is no longer present, the patient should be switched back to a buprenorphine formulation that allows finer dose titration. For patients moving from transmucosal buprenorphine taken together with CYP3A4 inhibitors, confirm through monitoring that the plasma buprenorphine level achieved with subQ buprenorphine is sufficient. Patients already receiving subQ buprenorphine who need to start a CYP3A4 inhibitor should be observed for indications of over-medication. Where signs and symptoms of buprenorphine toxicity or overdose develop and the coadministered drug cannot be reduced or stopped, decrease the buprenorphine dose. If the available doses make the target dose unattainable, stop therapy and manage the patient using a buprenorphine formulation that supports more precise dose adjustments 1.
Why it happens (mechanism)
Inhibition of CYP3A4-mediated metabolism of buprenorphine
How to manage this interaction
Keep taking both medicines exactly as prescribed unless your care team tells you otherwise. Here is what a care team typically does:
- The buprenorphine dose may need to be adjusted and individualized by your team while you are on palbociclib.
- They may monitor you more closely for signs of too much opioid, such as heavy drowsiness, confusion, or slow or shallow breathing.
- If palbociclib is later stopped, your team may adjust buprenorphine again and watch for withdrawal symptoms.
Tell your pharmacist and prescriber that you take both. Seek help right away for severe sleepiness or trouble breathing.
Management is individual — confirm any change with your pharmacist or prescriber.
Literature reports
1 report — tap to read
a) The impact of concurrently administered CYP3A4 inhibitors on buprenorphine exposure in individuals receiving subQ buprenorphine has not been investigated; nevertheless, interactions of this kind have been documented in studies employing transmucosal buprenorphine. The effects of buprenorphine may vary according to the route by which it is administered 1.
Common questions
Can I take Palbociclib and Buprenorphine together?
Palbociclib can raise buprenorphine levels and increase opioid side effects like sedation and slowed breathing; keep taking both as prescribed and let your care team adjust the buprenorphine dose and monitor you. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Palbociclib 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 Palbociclib and Buprenorphine interaction managed?
Keep taking both medicines exactly as prescribed unless your care team tells you otherwise. Here is what a care team typically does: The buprenorphine dose may need to be adjusted and individualized by your team while you are on palbociclib. They may monitor you more closely for signs of too much opioid, such as heavy drowsiness, confusion, or slow or shallow breathing. If palbociclib is later sto… Management is individual — always follow your own care team's guidance.
How strong is the evidence for this interaction?
The evidence is graded "probable". Good supporting evidence, though not definitively proven.
Questions for your pharmacist
- Does my dose of Palbociclib 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 (2)
- Product Information: BRIXADI(TM) subcutaneous extended-release injection, buprenorphine subcutaneous extended-release injection. Braeburn Inc (per FDA), Plymouth Meeting, PA, 2023. DailyMed
- Product Information: ZUBSOLV(R) sublingual tablets, buprenorphine naloxone sublingual tablets. Orexo US Inc (per FDA), Morristown, NJ, 2023. DailyMed
Keep reading about Buprenorphine
Keep reading about Palbociclib
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