Idelalisib 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
Idelalisib
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.
These two medicines can build up in a way you should know about. Buprenorphine (an opioid used for pain or opioid dependence) is broken down by a liver enzyme called CYP3A4. Idelalisib (Zydelig, used for certain blood cancers) slows that enzyme down. When the enzyme is slowed, buprenorphine can't clear as fast, so more of it stays in your body.
That can mean stronger, longer opioid effects, such as heavy drowsiness or slowed, shallow breathing. This is worth taking seriously, but it is very manageable. Don't stop or change either medicine on your own. Your care team can adjust your buprenorphine dose and watch you more closely so you stay safe and comfortable.
Mechanism: Idelalisib is a strong CYP3A4 inhibitor; buprenorphine undergoes CYP3A4-mediated metabolism (to norbuprenorphine). Inhibition reduces clearance, increasing buprenorphine exposure (AUC/Cmax).
Effect/direction: Increased buprenorphine effect, risk of prolonged opioid effects including sedation and respiratory depression.
- Evidence: Probable. Severity: Major. Onset: Unspecified.
- Management: If initiating idelalisib, consider reducing buprenorphine dose until stable; monitor frequently for sedation/respiratory depression. On idelalisib discontinuation, anticipate falling levels and monitor for withdrawal, adjusting dose upward as needed.
- For subQ depot formulations that limit titration, use a formulation permitting precise dose adjustment if toxicity emerges.
What happens
Increased buprenorphine exposure and an increased risk of buprenorphine-related adverse events
Interaction Deep Dive
Because a CYP3A4 inhibitor raises plasma buprenorphine concentrations, giving the two together can lead to extended opioid effects such as respiratory depression. When a patient on buprenorphine needs a CYP3A4 inhibitor, consider lowering 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 taking buprenorphine, consider raising the buprenorphine dose until stable effects are reached and monitor for signs of opioid withdrawal2. Should dose adjustment prove impossible once the CYP3A4 inhibitor is gone, switch the patient back to a buprenorphine formulation that allows finer dose titration. For patients transitioned from transmucosal buprenorphine given alongside CYP3A4 inhibitors, confirm through monitoring that the plasma buprenorphine level delivered by subQ buprenorphine is sufficient. For those already receiving subQ buprenorphine who then require a CYP3A4 inhibitor, watch for indications of over-medication. If buprenorphine toxicity or overdose emerges and the co-administered drug cannot be lowered or stopped, decrease the buprenorphine dose. When the available doses will not achieve the target dose, stop the treatment and manage the patient with a buprenorphine formulation that supports more precise dose adjustments1.
Why it happens (mechanism)
Inhibition of CYP3A4-mediated metabolism of buprenorphine
How to manage this interaction
Keep taking both medicines as prescribed unless your care team tells you otherwise. Here is how a team usually handles this combination:
- Your buprenorphine dose may need to be adjusted and individualized by your care team while you are on idelalisib.
- They may monitor you more closely for too much sedation or slow, shallow breathing, especially early on.
- When idelalisib is stopped, they may raise your buprenorphine dose again and watch for withdrawal symptoms.
- With long-acting (injectable) buprenorphine, a formulation that allows finer dose changes may be preferred if problems appear.
Call your pharmacist or prescriber right away if you feel unusually drowsy or notice slowed 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, these interactions have been documented in studies employing transmucosal buprenorphine. Buprenorphine's effects may vary according to the route of administration 1.
Common questions
Can I take Idelalisib and Buprenorphine together?
Idelalisib can raise buprenorphine levels by blocking its liver breakdown, increasing the risk of excess sedation and slowed breathing. Keep taking both as prescribed and let your care team adjust the buprenorphine dose and monitor you closely. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Idelalisib 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 Idelalisib and Buprenorphine interaction managed?
Keep taking both medicines as prescribed unless your care team tells you otherwise. Here is how a team usually handles this combination: Your buprenorphine dose may need to be adjusted and individualized by your care team while you are on idelalisib. They may monitor you more closely for too much sedation or slow, shallow breathing, especially early on. When idelalisib is stopped, they may raise y… 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 Idelalisib 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 Idelalisib
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