Buprenorphine and Difenoxin: 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
Difenoxin
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.
Both of these medicines can slow down your brain and breathing. Buprenorphine is a strong opioid pain reliever, and difenoxin is an opioid-type medicine used to slow down diarrhea. When you take them together, those calming effects can stack up. That can make you very drowsy, slow your breathing, and in serious cases lead to dangerously deep sedation.
There is also a smaller chance of a reaction called serotonin syndrome, which can cause shakiness, a fast heartbeat, sweating, or confusion. Please don't stop either drug on your own. Talk with your pharmacist or doctor. They can adjust things and keep a closer eye on you so this stays safe and manageable.
Interaction: Additive CNS and respiratory depression, plus a possible increased risk of serotonin syndrome, when buprenorphine (partial mu-opioid agonist) is combined with difenoxin (opioid-derived antidiarrheal).
- Mechanism: Additive serotonergic and CNS/respiratory depressant effects (PD interaction, not PK).
- Severity/Evidence: Major; substantiation probable. Onset unspecified.
- Risk: Profound sedation, respiratory depression, coma, death.
Management: Avoidance preferred. If coadministration is necessary, use lowest effective doses and monitor for sedation, respiratory depression, and signs of serotonin syndrome (clonus, hyperthermia, autonomic instability, altered mentation), especially at initiation and dose changes. Discontinue buprenorphine if serotonin syndrome is suspected.
What happens
An increased risk of serotonin syndrome and an increased risk of respiratory and CNS depression
Interaction Deep Dive
When buprenorphine is given together with a serotonergic CNS depressant, the effects on the CNS may be additive, raising the likelihood of serotonin syndrome as well as respiratory depression, deep sedation, coma, and death. Rather than using these agents together, stopping the other CNS depressant is the preferred approach. Depending on the situation, it may be suitable to observe the patient in a higher level of care or to implement a taper. In other situations, it may be appropriate to slowly wean the patient off a prescribed benzodiazepine or other CNS depressant, or to reduce it to the lowest dose that remains effective. Should concurrent use be required, watch for sedation, respiratory depression, and any signs and symptoms of serotonin syndrome. The patient should be observed closely, especially when therapy is being started and when the dose of the serotonergic agent is being adjusted. If serotonin syndrome is suspected, stop buprenorphine and consider alternative approaches for managing anxiety or insomnia21.
Why it happens (mechanism)
Additive serotonergic effects; additive CNS and respiratory depression
How to manage this interaction
Keep taking both exactly as prescribed unless your care team tells you otherwise. This combination is usually avoided, but when both are needed your team can manage it.
- Your team may use the lowest effective dose of each and monitor you more closely, especially when starting or adjusting a dose.
- They may consider tapering or choosing an alternative where possible.
- Watch for heavy drowsiness, slow or shallow breathing, confusion, or a fast heartbeat with sweating and shakiness, and get help right away if these occur.
Bring up any concerns with your pharmacist or prescriber before making changes.
Management is individual — confirm any change with your pharmacist or prescriber.
Literature reports
2 reports — tap to read
a) A Swedish epidemiological study found that patients receiving methadone- or buprenorphine-based medication-assisted treatment (MAT) together with benzodiazepines or other CNS depressants (for example, medications used to treat insomnia) have an increased risk of death. Between July 1, 2005 and December 31, 2012, researchers examined the risk of fatal overdose, non-overdose related mortality, and all-cause mortality by comparing periods when CNS depressants were prescribed to periods without CNS depressant therapy in MAT patients (aged 18 to 50). The findings showed a raised risk of all-cause mortality (adjusted hazard ratio (HR) 1.44; 95% CI, 0.93 to 2.23) and non-overdose related mortality (HR 1.74; 95% CI 1.00 to 3.01) with combined MAT and benzodiazepine treatment; however, these data were not deemed statistically significant. Although the results indicated an increased risk of fatal overdose, non-overdose mortality, and all-cause mortality during coadministration of MAT and non-benzodiazepines, only the fatal overdose and all-cause mortality data reached statistical significance; HR 2.34 (95% CI, 1.37 to 3.99) and HR 1.33 (95% CI, 1.12 to 2.45), respectively. No comparison was made between the benzodiazepine cohort and the non-benzodiazepine cohort because the authors did not adjust for the indication of use for the drugs 3.
b) A study of pooled nationwide death certificate data from 2010 to 2014 reported 3495 drug overdose deaths in 2014. Methadone and other CNS depressants were commonly cited as contributors to those deaths. Concurrent use of alprazolam was noted in 18.1% of cases, followed by oxycodone (10.1%), cocaine (9.6%), heroin (9%), and diazepam (6.6%). The FDA reported 322 drug overdose deaths in 2014 involving buprenorphine. Among these 322 deaths, 32.9% involved alprazolam, 17.4% involved clonazepam, 11.2% involved diazepam, 11.2% involved heroin, and 9.9% involved fentanyl. The absolute number of methadone-involved deaths was 10 times that of buprenorphine-involved deaths, though confounding factors and differences in drug utilization were not taken into account. It remains unknown whether the risk of overdose death with concurrent CNS depressant drugs differed between buprenorphine and methadone 3.
Common questions
Can I take Buprenorphine and Difenoxin together?
Combining buprenorphine and difenoxin can add up to dangerous sedation and slowed breathing, with a smaller chance of serotonin syndrome. Don't change either medicine on your own, and ask your pharmacist or doctor how to use them safely. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Buprenorphine and Difenoxin 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 Difenoxin interaction managed?
Keep taking both exactly as prescribed unless your care team tells you otherwise. This combination is usually avoided, but when both are needed your team can manage it. Your team may use the lowest effective dose of each and monitor you more closely, especially when starting or adjusting a dose. They may consider tapering or choosing an alternative where possible. Watch for heavy drowsiness, slow… 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 Difenoxin 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 (3)
- Product Information: BRIXADI(TM) subcutaneous extended-release injection, buprenorphine subcutaneous extended-release injection. Braeburn Inc (per FDA), Plymouth Meeting, PA, 2023. DailyMed
- Product Information: SUBUTEX(R) sublingual tablets, buprenorphine sublingual tablets. Indivior Inc (per FDA), North Chesterfield, VA, 2021. DailyMed
- US Food and Drug Administration (FDA): Drug Safety Communications: FDA urges caution about withholding opioid addiction medications from patients taking benzodiazepines or CNS depressants: careful medication management can reduce risks. US Food and Drug Administration (FDA). Silver Spring, MD. 2017.
Keep reading about Buprenorphine
Keep reading about Difenoxin
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