Morphine Injection and Fluvoxamine: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Fluvoxamine
No brand names on recordMorphine Injection
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
Increased morphine exposure, increased risk of morphine-related adverse effects (hypotension, respiratory depression, profound sedation, coma) and an increased risk of serotonin syndrome
Interaction Deep Dive
Concomitant use of morphine with serotonergic P-gp inhibitor may lead to increased exposure of morphine by two-fold, increased risk of adverse effects, including respiratory, CNS depression and concomitant use has resulted in serotonin syndrome. If concomitant use is needed, carefully observe the patient, particularly during treatment initiation and dose adjustments. Monitor for signs of CNS depression. Evaluate patients for signs of respiratory depression that may be greater than otherwise expected and decrease the dosage of morphine and/or P-gp inhibitor as necessary. Discontinue morphine if serotonin syndrome is suspected4132.
Why it happens (mechanism)
Inhibition of P-gp-mediated efflux transport by morphine; additive serotonergic effects
Literature reports
1 report — tap to read
Common questions
Can I take Morphine Injection and Fluvoxamine together?
Increased morphine exposure, increased risk of morphine-related adverse effects (hypotension, respiratory depression, profound sedation, coma) and an increased risk of serotonin syndrome Always confirm with your pharmacist or prescriber before making any change.
How serious is the Morphine Injection and Fluvoxamine 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 Morphine Injection or Fluvoxamine 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 (4)
- Product Information: MS CONTIN(R) oral extended-release tablets, morphine sulfate oral extended-release tablets. Purdue Pharma LP (per FDA), Stamford, CT, 2023. DailyMed
- Product Information: INFUMORPH intrathecal, epidural injection, morphine sulfate intrathecal, epidural injection. Hikma Pharmaceuticals USA Inc (per FDA), Berkeley Heights, NJ, 2023. DailyMed
- Product Information: Morphine sulfate oral solution, morphine sulfate oral solution. Hikma Pharmaceuticals USA Inc (per FDA), Berkeley Heights, NJ, 2023. DailyMed
- Product Information: DURAMORPH intravenous, epidural, intrathecal injection, morphine sulfate intravenous, epidural, intrathecal injection. Hikma Pharmaceuticals USA Inc (Per FDA), Berkeley, NJ, 2023. DailyMed
Keep reading about Fluvoxamine
Keep reading about Morphine Injection
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