Buprenorphine and Letermovir Injection: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Buprenorphine
Letermovir Injection
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.
What happens
Increased buprenorphine exposure and an increased risk of buprenorphine-related adverse events
Interaction Deep Dive
Prolonged opioid effects, including respiratory depression, may occur with concomitant use of buprenorphine and a CYP3A4 inhibitor due to increased plasma concentrations of buprenorphine. If use of a CYP3A4 inhibitor is necessary in a patient receiving buprenorphine, consider reducing the dose of buprenorphine until stable drug effects are achieved and monitor for sedation and respiratory depression frequently. When discontinuing a CYP3A4 inhibitor in a patient receiving buprenorphine therapy, consider a buprenorphine dose increase until stable drug effects are achieved and monitor for signs of opioid withdrawal1. If the dosage cannot be adjusted in the absence of the CYP3A4 inhibitor, transition the patient back to a formulation of buprenorphine that permits more precise dose adjustments. In patients converted from a regimen of transmucosal buprenorphine coadministered with CYP3A4 inhibitors, monitor to ensure that the plasma buprenorphine level provided by subQ buprenorphine is adequate. In patients already on subQ buprenorphine who require a CYP3A4 inhibitor, monitor for signs and symptoms of over-medication. If signs and symptoms of buprenorphine toxicity or overdose occur but the concomitant medication cannot be reduced or discontinued, reduce the dose of buprenorphine. If available doses do not permit achievement of the desired dose, discontinue treatment and treat the patient with a formulation of buprenorphine that permits more precise dose adjustments 2.
Why it happens (mechanism)
Inhibition of CYP3A4-mediated metabolism of buprenorphine
Literature reports
1 report — tap to read
a) The effects of coadministered CYP3A4 inhibitors on buprenorphine exposure in subjects treated with subQ buprenorphine have not been studied; however, such interactions have been established in studies using transmucosal buprenorphine. The effects of buprenorphine may be dependent on the route of administration 2.
Common questions
Can I take Buprenorphine and Letermovir Injection together?
Increased buprenorphine exposure and an increased risk of buprenorphine-related adverse events Always confirm with your pharmacist or prescriber before making any change.
How serious is the Buprenorphine and Letermovir Injection 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 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 Letermovir Injection 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: ZUBSOLV(R) sublingual tablets, buprenorphine naloxone sublingual tablets. Orexo US Inc (per FDA), Morristown, NJ, 2023. DailyMed
- Product Information: BRIXADI(TM) subcutaneous extended-release injection, buprenorphine subcutaneous extended-release injection. Braeburn Inc (per FDA), Plymouth Meeting, PA, 2023. DailyMed
Keep reading about Buprenorphine
Keep reading about Letermovir Injection
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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