Buprenorphine and Lofexidine: 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
Lofexidine
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.
Buprenorphine (used for pain or opioid treatment) and lofexidine (often used to ease opioid withdrawal) can add together in two ways when taken at the same time. First, both can slow down your brain and body, so you may feel more sleepy, dizzy, or slow to react. Second, both can gently affect your heart's rhythm (something called the QT interval).
This concern is based mostly on theory and small studies, so try not to worry. Your care team can manage it easily. Be careful about driving or using machines until you know how you feel, and let your pharmacist or doctor know you take both so they can keep an eye on things.
Effect: Additive CNS depression and additive QT prolongation with concomitant buprenorphine and lofexidine. Neither drug's activation depends on the other; this is a pharmacodynamic, not enzymatic, interaction.
- Direction/magnitude: In buprenorphine-maintained patients, adding lofexidine increased QTcF by ~15 ms (~9.1 ms with methadone).
- Onset: Unspecified. Evidence: Theoretical/limited. Severity: Major.
- Management: Monitor ECG for QTc; assess for excessive sedation/respiratory depression. Correct electrolytes, review other QT-prolonging or CNS-depressant agents. Counsel against driving/operating machinery.
What happens
Increased risk of CNS depressant effects and increased risk of QT interval prolongation
Interaction Deep Dive
Taking lofexidine together with this drug can heighten CNS depressant activity and raise the likelihood of QT interval prolongation. When lofexidine was introduced in patients already receiving buprenorphine or methadone (agents capable of prolonging the QT interval), QTcF rose by 15 and 9.1 milliseconds, respectively. ECG monitoring is warranted when lofexidine and this drug are given concurrently. In addition, patients should exercise caution when driving or operating heavy machinery, or avoid these activities altogether1.
Why it happens (mechanism)
Additive CNS depression; additive effects on QT interval
How to manage this interaction
If you are prescribed both, keep taking them exactly as directed unless your prescriber tells you otherwise. Your care team can manage this well.
- Your team may check your heart rhythm with an ECG while you use both drugs together.
- Watch for strong drowsiness, dizziness, or feeling unusually sleepy, and avoid driving or operating heavy machinery until you know how the combination affects you.
- Tell your pharmacist or doctor about any other medicines you take, since some can add to the heart-rhythm or sedation effect.
- Report fainting, palpitations, or very slow, shallow breathing right away.
Management is individual — confirm any change with your pharmacist or prescriber.
Literature reports
2 reports — tap to read
a) In a study involving 18 patients maintained on methadone (80 to 120 mg/day), the concurrent administration of lofexidine (2.88 mg/day) produced a maximum mean rise in QTcF of 9.1 milliseconds relative to the methadone-alone baseline 1.
b) In a study involving 21 patients maintained on buprenorphine (16 to 24 mg/day), the concurrent administration of lofexidine (2.88 mg/day) produced a maximum mean rise in QTcF of 15 milliseconds relative to the buprenorphine-alone baseline 1.
Common questions
Can I take Buprenorphine and Lofexidine together?
Taking buprenorphine and lofexidine together can add up to more drowsiness and a small effect on your heart rhythm, so your team may check an ECG and you should be cautious about driving until you know how you feel. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Buprenorphine and Lofexidine 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 Lofexidine interaction managed?
If you are prescribed both, keep taking them exactly as directed unless your prescriber tells you otherwise. Your care team can manage this well. Your team may check your heart rhythm with an ECG while you use both drugs together. Watch for strong drowsiness, dizziness, or feeling unusually sleepy, and avoid driving or operating heavy machinery until you know how the combination affects you. Tell… 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 Buprenorphine or Lofexidine 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: LUCEMYRA(TM) oral tablets, lofexidine oral tablets. US WorldMeds LLC (per FDA), Louisville, KY, 2018. DailyMed
Keep reading about Buprenorphine
Keep reading about Lofexidine
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