Cyproheptadine 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
Cyproheptadine
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.
You've been prescribed buprenorphine (an opioid used for pain or opioid dependence) along with cyproheptadine (an antihistamine). Both of these can slow down your gut and both can make you feel sleepy or slowed down.
When taken together, they can add up. That means a higher chance of severe constipation (in rare cases the bowel can nearly stop moving), trouble urinating, and feeling extra drowsy or foggy. This concern is based on how these drugs work rather than lots of reports, but it's worth watching. The good news is your care team can manage this easily by keeping an eye on you and adjusting things as needed. Let them know if you get very constipated, can't pee, or feel unusually sleepy.
Effect: Additive risk of reduced GI motility (severe constipation, potential paralytic ileus), urinary retention, and additive CNS depression.
Mechanism: Cyproheptadine has anticholinergic and antihistaminic (sedating) properties; buprenorphine is an opioid that slows gut motility and causes CNS depression. Effects are additive (PD interaction). Neither is a prodrug here.
- Direction: Increased buprenorphine-associated adverse effects.
- Onset: Unspecified.
- Evidence: Theoretical.
- Management: Monitor for constipation, reduced gastric motility, urinary retention, and excess sedation/respiratory depression. Consider bowel regimen; dose adjust or choose an alternative if warranted.
What happens
An increased risk of paralytic ileus and an increased risk of CNS depression
Interaction Deep Dive
When buprenorphine is given together with cyproheptadine (an anticholinergic agent), the combination can lead to urinary retention or severe constipation that progresses to paralytic ileus. During concurrent administration of buprenorphine and cyproheptadine, watch for indications of urinary retention or diminished gastric motility1. Furthermore, because cyproheptadine is an antihistamine, its use alongside CNS depressants such as buprenorphine may produce additive effects, thereby raising the likelihood of CNS depression2.
Why it happens (mechanism)
Additive effects on gastric motility; additive CNS depression
How to manage this interaction
Keep taking both medications exactly as prescribed unless your prescriber tells you otherwise. Your care team can manage this combination well with a little extra attention.
- Your team may monitor you more closely for constipation, trouble urinating, and excess drowsiness.
- Doses may be adjusted and individualized by your care team, or an alternative may be chosen if problems come up.
- Report severe or worsening constipation, belly bloating or pain, inability to urinate, or unusual sleepiness or slowed breathing promptly.
Staying well hydrated and asking your pharmacist about a stool softener plan can also help. Bring up any questions with your pharmacist or prescriber.
Management is individual — confirm any change with your pharmacist or prescriber.
Common questions
Can I take Cyproheptadine and Buprenorphine together?
Taking buprenorphine with cyproheptadine can add up to cause severe constipation, trouble urinating, and extra drowsiness. Keep taking both as prescribed and tell your care team about any of these symptoms so they can monitor and adjust. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Cyproheptadine 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 Cyproheptadine and Buprenorphine interaction managed?
Keep taking both medications exactly as prescribed unless your prescriber tells you otherwise. Your care team can manage this combination well with a little extra attention. Your team may monitor you more closely for constipation, trouble urinating, and excess drowsiness. Doses may be adjusted and individualized by your care team, or an alternative may be chosen if problems come up. Report severe… 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 Cyproheptadine 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: Cyproheptadine HCl oral solution, cyproheptadine HCl oral solution. Lannett Company Inc (per DailyMed), Philadelphia, PA, 2017.
Keep reading about Buprenorphine
Keep reading about Cyproheptadine
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major · moderate · minor — check everything you take with our drug–supplement interaction checker.
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