Buprenorphine and Doxylamine: 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
Doxylamine
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.
These two both slow down your body's activity, so taking them together can add up. Buprenorphine (like Belbuca or Suboxone) is a strong opioid, and doxylamine (the sleep aid in Unisom or ZzzQuil) is a sedating antihistamine. On their own each can make you sleepy. Together they can make you very drowsy and, more seriously, can slow your breathing. In rare cases that can be dangerous.
The good news is this is manageable. Please don't stop either medicine on your own. Talk with your pharmacist or doctor, who may suggest a safer sleep option, a lower dose, or closer monitoring so you stay safe.
Mechanism: Additive CNS depression. Buprenorphine (partial mu-opioid agonist) combined with doxylamine (sedating H1-antihistamine) produces summative sedative and respiratory-depressant effects. This is a pharmacodynamic interaction, not enzyme-mediated; neither agent's prodrug status is relevant.
Direction/effect: Increased risk of profound sedation, respiratory depression, coma, and death.
- Severity: Major; evidence: probable (epidemiologic data link MAT plus CNS depressants to increased overdose mortality).
- Onset: Unspecified.
- Management: Avoid concurrent use where possible; prefer non-sedating alternatives for insomnia. If combined, use lowest effective dose, monitor respiratory status and sedation, and consider a higher level of care. Do not withhold MAT.
What happens
An increased risk of respiratory depression and CNS depression
Interaction Deep Dive
When buprenorphine is given together with a CNS depressant, the effects on the central nervous system can be additive, raising the likelihood of respiratory depression, profound sedation, coma, and death. Discontinuing CNS depressants is preferable to using them at the same time. Certain situations may call for monitoring in a higher level of care or for a taper. In other situations, it may be suitable to gradually withdraw a patient from a prescribed CNS depressant or to reduce the dose to the lowest amount that remains effective. Should concurrent use be required, exercise caution in monitoring and management, and consider alternative treatments for anxiety or insomnia2. A Swedish epidemiological study found that patients undergoing methadone- or buprenorphine-based medication-assisted treatment (MAT) together with benzodiazepines or other CNS depressants (for instance, medications used for insomnia) face an elevated risk of death. Based on an analysis of pooled nationwide death certificate data spanning 2010 to 2014, most overdose deaths involving buprenorphine and methadone also involved concurrent CNS depressant use. Whether the risk of overdose death from concurrent CNS depressant drugs varied between buprenorphine and methadone is not known 3.
Why it happens (mechanism)
Additive CNS depression
How to manage this interaction
What your care team may do:
- Prefer a non-sedating option for sleep instead of doxylamine, since better alternatives often exist.
- If both are needed, use the lowest effective dose and watch you more closely for excess sedation or slowed breathing.
- Your doses may be adjusted and individualized by your care team.
What you should do:
- Keep taking your buprenorphine as prescribed; it is important for your treatment.
- Before using doxylamine or any sleep aid, check with your pharmacist or prescriber.
- Seek help right away for very heavy drowsiness, confusion, or slow/shallow breathing.
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, investigators 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 among MAT-prescribed 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 MAT plus benzodiazepine treatment; however, these data were not regarded as statistically significant. Although the results indicated a heightened risk of fatal overdose, non-overdose mortality, and all-cause mortality during periods of concurrent MAT and non-benzodiazepine use, only the fatal overdose and all-cause mortality data were considered statistically significant; HR 2.34 (95% CI, 1.37 to 3.99) and HR 1.33 (95% CI, 1.12 to 2.45), respectively. The authors did not compare the benzodiazepine cohort with the non-benzodiazepine cohort because they did not adjust for the indication of use for the drugs 3.
b) In a study of pooled nationwide death certificate data from 2010 to 2014, 3495 drug overdose deaths were reported in 2014. Methadone along with other CNS depressants were often cited as contributing agents in those deaths. Concomitant ALPRAZolam use 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 that involved 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 the number of buprenorphine-involved deaths, although confounding factors and differences in drug utilization were not taken into account. Whether the risk of overdose death with concurrent CNS depressant drugs differed between buprenorphine and methadone is unknown 3.
Common questions
Can I take Buprenorphine and Doxylamine together?
Combining buprenorphine with doxylamine can add up to dangerous drowsiness and slowed breathing, so ask your pharmacist or doctor for a safer sleep option before using both. Never stop your buprenorphine on your own. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Buprenorphine and Doxylamine 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 Doxylamine interaction managed?
What your care team may do: Prefer a non-sedating option for sleep instead of doxylamine, since better alternatives often exist. If both are needed, use the lowest effective dose and watch you more closely for excess sedation or slowed breathing. Your doses may be adjusted and individualized by your care team. What you should do: Keep taking your buprenorphine as prescribed; it is important for yo… 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 Doxylamine 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 Doxylamine
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