Fentanyl Transdermal Patch and Levomilnacipran: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Levomilnacipran
No brand names on recordFentanyl Transdermal Patch
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.
What happens
An increased risk of serotonin syndrome
Interaction Deep Dive
Levomilnacipran is a serotonergic drug; concomitant use with another agent that affects the serotonergic neurotransmitter system may result in an increased risk of potentially life-threatening serotonin syndrome and should be approached with extreme caution. Monitor all patients taking levomilnacipran with other serotonergic drugs for the emergence of serotonin syndrome. If serotonin syndrome develops, discontinue both agents and initiate supportive symptomatic therapy. If concomitant use of levomilnacipran with other serotonergic drugs is clinically warranted, inform patients of the increased risk for serotonin syndrome and monitor for symptoms1.
Why it happens (mechanism)
Additive serotonergic effects
Common questions
Can I take Fentanyl Transdermal Patch and Levomilnacipran together?
An increased risk of serotonin syndrome Always confirm with your pharmacist or prescriber before making any change.
How serious is the Fentanyl Transdermal Patch and Levomilnacipran 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 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 Fentanyl Transdermal Patch or Levomilnacipran 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: FETZIMA(R) oral extended-release capsules, levomilnacipran oral extended-release capsules. AbbVie Inc (per FDA), North Chicago, IL, 2023. DailyMed
Keep reading about Levomilnacipran
Keep reading about Fentanyl Transdermal Patch
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Prescription drugs aren't the whole picture — herbal and dietary supplements can interact with them too. From the evidence-graded Natural Medicines database:
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