Solifenacin 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
Solifenacin
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.
Let's talk about taking buprenorphine (for pain or opioid treatment) together with solifenacin (Vesicare, for an overactive bladder). Both of these can slow down your gut and make it harder to pee. When you take them together, those effects can add up, so you may notice bad constipation or trouble urinating. In rare cases, very slowed digestion can become serious. Both drugs may also have a small effect on your heart's rhythm.
The good news is this is very manageable. Your care team can watch for these signs and adjust things as needed. Please don't stop either medicine on your own. Just let your pharmacist or doctor know if you notice constipation or trouble going to the bathroom.
Effect: Additive risk of reduced GI motility (constipation, urinary retention, potential paralytic ileus) and additive QT prolongation.
- Mechanism: Buprenorphine's opioid effect on gut motility plus solifenacin's anticholinergic effect are additive; both agents carry QT-prolonging potential. Neither is a prodrug relevant here.
- Direction: Additive PD interaction, not a PK/enzyme interaction.
- Evidence: Theoretical; severity rated major. Onset unspecified.
- Management: Monitor for urinary retention and reduced gastric motility. Assess QT risk factors (hypokalemia, hypomagnesemia, bradycardia, HF, baseline QT prolongation, digitalis therapy). Consider ECG/electrolyte monitoring in at-risk patients; consider alternatives where feasible.
What happens
An increased risk of paralytic ileus and an increased risk of QT interval prolongation
Interaction Deep Dive
Buprenorphine should not be given together with medications capable of lengthening the QT interval2. When buprenorphine is taken alongside an anticholinergic drug, the combination can lead to urinary retention or severe constipation, potentially progressing to paralytic ileus. For this reason, patients receiving buprenorphine concurrently with anticholinergic agents should be observed for indications of urinary retention or decreased gastric motility. It remains unknown what risk arises from pairing buprenorphine with other agents that prolong QT. These findings should be weighed in clinical decision-making when buprenorphine is prescribed to individuals who have risk factors including hypokalemia, bradycardia, recent conversion from atrial fibrillation, congestive heart failure, digitalis therapy, baseline QT prolongation, subclinical long-QT syndrome, or severe hypomagnesemia 1.
Why it happens (mechanism)
Additive effects on gastric motility; additive QT interval prolongation
How to manage this interaction
Keep taking both medications exactly as prescribed unless your care team tells you otherwise. Here is how this is typically handled:
- Your team may monitor you more closely for constipation, trouble urinating, or a bloated, painful belly.
- If you have heart-rhythm risk factors (low potassium or magnesium, slow heart rate, heart failure), your team may check your ECG or bloodwork and may consider an alternative bladder medication.
- Stay well hydrated and mention any bowel or bladder changes.
Call your pharmacist or doctor if you cannot have a bowel movement, cannot urinate, or have severe belly pain.
Management is individual — confirm any change with your pharmacist or prescriber.
Common questions
Can I take Solifenacin and Buprenorphine together?
Together these drugs can add up to worse constipation and urinary retention (rarely a serious gut blockage) and may both nudge the heart rhythm, so watch for these signs and tell your care team, who can monitor you or adjust treatment. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Solifenacin 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 Solifenacin and Buprenorphine interaction managed?
Keep taking both medications exactly as prescribed unless your care team tells you otherwise. Here is how this is typically handled: Your team may monitor you more closely for constipation, trouble urinating, or a bloated, painful belly. If you have heart-rhythm risk factors (low potassium or magnesium, slow heart rate, heart failure), your team may check your ECG or bloodwork and may consider an… 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 Solifenacin 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: BELBUCA(TM) buccal film, buprenorphine buccal film. Endo Pharmaceuticals Inc. (per FDA), Malvern, PA, 2016.
Keep reading about Buprenorphine
Keep reading about Solifenacin
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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