Suvorexant and Morphine Injection: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Suvorexant
Morphine 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 risk of profound sedation, respiratory depression, hypotension, coma, increased morphine exposure and an increased risk of morphine-related adverse effects
Interaction Deep Dive
Concomitant use of morphine and CNS depressant that is also a P-gp inhibitor may increase the exposure of morphine by two-fold and increase the risk of increased risk of profound sedation, respiratory depression, hypotension, coma and opioid overdose. Reserve the concomitant use of morphine and CNS depressants to patients for whom alternatives are inadequate. If concomitant use is necessary, use the lowest dose and shortest duration necessary to achieve treatment goals. Consider using a lower dose of morphine or the CNS depressant and closely monitor for sedation. 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. The risk of opioid overdose is increased with concurrent use of morphine with CNS depressants. Consider prescribing naloxone for the emergency treatment of opioid overdose132.
Why it happens (mechanism)
Additive CNS depression effects; inhibition of P-gp-mediated efflux transport by morphine
Common questions
Can I take Suvorexant and Morphine Injection together?
Increased risk of profound sedation, respiratory depression, hypotension, coma, increased morphine exposure and an increased risk of morphine-related adverse effects Always confirm with your pharmacist or prescriber before making any change.
How serious is the Suvorexant and Morphine Injection 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 Suvorexant or Morphine Injection 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: MS CONTIN(R) oral extended-release tablets, morphine sulfate oral extended-release tablets. Purdue Pharma LP (per FDA), Stamford, CT, 2023. DailyMed
- Product Information: Morphine sulfate oral tablets, morphine sulfate oral tablets. Hikma Pharmaceuticals USA Inc.(Per FDA), Berkeley, NJ, 2023. DailyMed
- Product Information: Morphine sulfate oral solution, morphine sulfate oral solution. Hikma Pharmaceuticals USA Inc (per FDA), Berkeley Heights, NJ, 2023. DailyMed
Keep reading about Suvorexant
Keep reading about Morphine Injection
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