Nafcillin 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
Nafcillin
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.
Let's talk about taking buprenorphine (like Belbuca, Suboxone, or Sublocade) together with the antibiotic nafcillin. Nafcillin can speed up how fast your body breaks down buprenorphine. That means there may be less buprenorphine in your system than usual, so it may not work as well. If you take buprenorphine for pain or for opioid treatment, you might notice your dose feels weaker or you start having withdrawal symptoms like feeling anxious, achy, sweaty, or having an upset stomach.
The good news is your care team can manage this. Please don't stop or change either medicine on your own. Just let your doctor or pharmacist know you're on both so they can watch you closely and adjust your buprenorphine if needed.
Effect: Nafcillin, a CYP3A4 inducer, may increase buprenorphine metabolism, reducing buprenorphine plasma exposure and efficacy. Risk of opioid withdrawal (buprenorphine is active drug, not a prodrug; induction lowers, not raises, its effect).
- Mechanism: Induction of CYP3A4-mediated buprenorphine metabolism.
- Evidence/severity: Probable; rated major. Onset unspecified (induction typically develops over days to weeks).
- Management: Monitor for withdrawal; if inducer needed, consider increasing buprenorphine dose to stable effect. On inducer discontinuation, consider dose reduction and monitor for respiratory depression. For subQ formulations, verify adequate levels; if precise titration is required, use a formulation allowing finer dose adjustment.
What happens
Reduced buprenorphine exposure and reduced efficacy of buprenorphine
Interaction Deep Dive
Combining buprenorphine with a CYP3A4 inducer can trigger opioid withdrawal symptoms because plasma buprenorphine concentrations fall. When a patient on buprenorphine must also receive a CYP3A4 inducer, one option is to raise the buprenorphine dose until stable drug effects are reached, while watching for signs of withdrawal. Conversely, if a CYP3A4 inducer is stopped in a patient taking buprenorphine, a reduction in the buprenorphine dose should be considered, along with monitoring for respiratory depression2. Should dose adjustment prove impossible once the CYP3A4 inducer is gone, the patient should be moved back to a buprenorphine formulation that allows finer dose titration. For patients switched from transmucosal buprenorphine taken together with CYP3A4 inducers, confirm through monitoring that the plasma buprenorphine level achieved by subQ buprenorphine is sufficient. Patients already receiving subQ buprenorphine who then need a CYP3A4 inducer should be monitored for withdrawal. When the buprenorphine dose is inadequate while the concomitant drug is present, and that drug can neither be lowered nor stopped, the buprenorphine dose should be modified. If the doses on hand cannot deliver the target dose, use a buprenorphine formulation that permits more precise dose adjustments1.
Why it happens (mechanism)
Induction of CYP3A4-mediated metabolism of buprenorphine
How to manage this interaction
Keep taking both medications exactly as prescribed, and let your care team know you are on them together.
- Your team may monitor you more closely for withdrawal signs (anxiety, aches, sweating, nausea, restlessness) while you are on nafcillin.
- Your buprenorphine dose may need to be adjusted and individualized to keep it working well, then adjusted again when the antibiotic is stopped.
- When nafcillin is stopped, your team may lower the buprenorphine dose and watch for over-sedation or slowed breathing.
Report new withdrawal symptoms or a return of pain to your pharmacist or prescriber so they can respond.
Management is individual — confirm any change with your pharmacist or prescriber.
Literature reports
1 report — tap to read
a) The impact of a concurrently administered CYP3A4 inducer on buprenorphine exposure in patients 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 Nafcillin and Buprenorphine together?
Nafcillin can lower buprenorphine levels and may trigger withdrawal or reduced effect; keep taking both as prescribed and ask your care team to monitor you and adjust the buprenorphine dose as needed. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Nafcillin 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 Nafcillin and Buprenorphine interaction managed?
Keep taking both medications exactly as prescribed, and let your care team know you are on them together. Your team may monitor you more closely for withdrawal signs (anxiety, aches, sweating, nausea, restlessness) while you are on nafcillin. Your buprenorphine dose may need to be adjusted and individualized to keep it working well, then adjusted again when the antibiotic is stopped. When nafcilli… 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 Nafcillin 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 Nafcillin
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