Lenacapavir 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
Lenacapavir
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 buprenorphine (a medicine for pain or opioid use) along with lenacapavir (an HIV medicine). When these two are used together, the amount of buprenorphine in your body could go up or down. If it goes up, you might feel more side effects like sleepiness, slow breathing, or dizziness. If it goes down, the buprenorphine might not work as well.
The good news is this is mostly a theoretical concern, and your care team can handle it easily. They may start you on a low dose and adjust it based on how you feel. If you notice any new drowsiness or your pain isn't controlled, just let your pharmacist or doctor know.
Effect: Altered buprenorphine exposure (may increase or decrease) when co-administered with lenacapavir.
- Mechanism: Unknown; lenacapavir has mixed effects on CYP3A4 and transporters, and buprenorphine is a CYP3A4/2C8 substrate, so exposure could shift either direction.
- Direction/magnitude: Unpredictable, not quantified.
- Evidence: Theoretical; onset unspecified.
- Management: When starting buprenorphine in a lenacapavir-treated patient, titrate carefully using the lowest feasible initial/maintenance dose. When starting lenacapavir in a buprenorphine-treated patient, buprenorphine dose may need adjustment. Monitor for sedation, respiratory depression, or loss of analgesic/OUD efficacy.
What happens
Increased or reduced buprenorphine exposure
Interaction Deep Dive
When starting buprenorphine in individuals already receiving lenacapavir, titrate the buprenorphine dose cautiously toward the intended effect, using the lowest possible starting or maintenance dose. Conversely, when lenacapavir is being started in individuals already on buprenorphine, the buprenorphine dose may require adjustment. Watch for clinical signs and symptoms1.
Why it happens (mechanism)
Unknown
How to manage this interaction
Keep taking both medicines exactly as prescribed unless your care team tells you otherwise. Here is how your team typically manages this:
- Careful dosing: When buprenorphine is started, your team may begin with the lowest reasonable dose and adjust it up slowly to the right effect.
- Individualized adjustment: If lenacapavir is added while you already take buprenorphine, your buprenorphine dose may need to be adjusted and individualized by your care team.
- Monitoring: Watch for new drowsiness, slowed breathing, or poorly controlled pain or cravings.
Tell your pharmacist or prescriber about any changes so they can fine-tune your dose.
Management is individual — confirm any change with your pharmacist or prescriber.
Common questions
Can I take Lenacapavir and Buprenorphine together?
Combining buprenorphine and lenacapavir may raise or lower buprenorphine levels, so your care team will start low, adjust the dose to fit you, and watch for side effects or reduced effect. Report any new drowsiness, slow breathing, or return of pain or cravings. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Lenacapavir 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 Lenacapavir and Buprenorphine interaction managed?
Keep taking both medicines exactly as prescribed unless your care team tells you otherwise. Here is how your team typically manages this: Careful dosing: When buprenorphine is started, your team may begin with the lowest reasonable dose and adjust it up slowly to the right effect. Individualized adjustment: If lenacapavir is added while you already take buprenorphine, your buprenorphine dose may n… 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 Lenacapavir 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: SUNLENCA(R) oral tablets, subcutaneous injection, lenacapavir oral tablets, subcutaneous injection. Gilead Sciences Inc (per FDA), Foster City, CA, 2022. DailyMed
Keep reading about Buprenorphine
Keep reading about Lenacapavir
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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