Buprenorphine and Darunavir: 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
Darunavir
No brand names on record
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 interact. Buprenorphine is an opioid used for pain or opioid dependence. Darunavir is an HIV medicine that also slows down a liver enzyme (called CYP3A4) that normally helps clear buprenorphine from your body.
When that enzyme is slowed, buprenorphine can build up to higher levels. That can make its effects stronger and last longer, including extra sleepiness or slowed breathing. The good news is your care team can manage this safely by adjusting your buprenorphine dose and watching you more closely. Please don't stop or change either medicine on your own. Talk with your pharmacist or doctor, and let them know right away if you feel unusually drowsy or short of breath.
Effect: Darunavir inhibits CYP3A4, reducing buprenorphine metabolism and increasing buprenorphine plasma exposure, raising risk of opioid adverse effects (sedation, prolonged respiratory depression). Neither is metabolized to a more active opioid via this pathway, so effect is increased, not reduced.
- Direction: increased buprenorphine exposure
- Severity/evidence: major; probable
- Onset: unspecified
Management: If starting darunavir in a buprenorphine patient, consider reducing the buprenorphine dose until stable, monitor frequently for sedation/respiratory depression. On darunavir discontinuation, anticipate reduced levels; consider a dose increase and monitor for withdrawal. Prefer formulations allowing precise titration; for subQ depot products, monitor for over-medication.
What happens
Increased buprenorphine exposure and an increased risk of buprenorphine-related adverse events
Interaction Deep Dive
Because plasma buprenorphine levels rise when buprenorphine is taken together with a CYP3A4 inhibitor, extended opioid effects such as respiratory depression can result. When a patient on buprenorphine must also receive a CYP3A4 inhibitor, it may be appropriate to lower the buprenorphine dose until drug effects stabilize, while checking regularly for sedation and respiratory depression. Conversely, on stopping a CYP3A4 inhibitor in someone treated with buprenorphine, a higher buprenorphine dose may be warranted until effects stabilize, with monitoring for indications of opioid withdrawal2. Should dose adjustment prove impossible once the CYP3A4 inhibitor is gone, the patient should be switched back to a buprenorphine formulation that allows finer dose control. For patients moved from transmucosal buprenorphine given alongside CYP3A4 inhibitors, verify that subQ buprenorphine delivers an adequate plasma buprenorphine level. For those already receiving subQ buprenorphine who then need a CYP3A4 inhibitor, watch for signs and symptoms of over-medication. If buprenorphine toxicity or overdose signs and symptoms develop and the co-administered medication cannot be lowered or stopped, decrease the buprenorphine dose. When the available doses will not allow the target dose to be reached, stop treatment and manage the patient using a buprenorphine formulation permitting 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 as prescribed unless your care team tells you otherwise. This interaction is manageable with the right adjustments and monitoring.
- Your team may lower your buprenorphine dose while you are on darunavir, and adjust it back up if darunavir is stopped, individualized to you.
- They may monitor you more closely for sedation and slowed breathing (and for withdrawal signs when darunavir is stopped).
- A formulation that allows more precise dose changes may be preferred.
Call your prescriber or pharmacist right away if you notice heavy drowsiness, confusion, or slow or shallow 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 patients receiving subQ buprenorphine has not been investigated; nevertheless, such interactions have been documented in studies that used transmucosal buprenorphine. Buprenorphine's effects may vary according to the route of administration 1.
Common questions
Can I take Buprenorphine and Darunavir together?
Darunavir can raise buprenorphine levels and prolong opioid effects like slowed breathing, so your care team may lower your buprenorphine dose and watch you closely. Don't change either drug on your own and report any unusual drowsiness or breathing trouble. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Buprenorphine and Darunavir 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 Darunavir interaction managed?
Keep taking both medicines as prescribed unless your care team tells you otherwise. This interaction is manageable with the right adjustments and monitoring. Your team may lower your buprenorphine dose while you are on darunavir, and adjust it back up if darunavir is stopped, individualized to you. They may monitor you more closely for sedation and slowed breathing (and for withdrawal signs when d… 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 Buprenorphine or Darunavir 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 Darunavir
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