Drug Interaction Report

Alvimopan and Morphine Sulfate Liposome: Interaction Details

A pharmacist-reviewed analysis of the Alvimopan and Morphine Sulfate Liposome interaction: the documented clinical effects, severity rating, onset, mechanism, and management considerations, with cited references throughout.

AI-assisted, pharmacist-reviewed · Source data updated Jul 11, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature

Morphine Sulfate Liposome

No brand names on record
+

Alvimopan

Entereg Entereg®
Dr. Brian Staiger, PharmD, BCPS
Medically reviewed by
Dr. Brian Staiger, PharmD, BCPS
Updated Jul 11, 2026
Editorial policy · Data sources
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Interaction severity
Major
Potentially serious — often needs a change or close monitoring.
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.

Of 5 documented Alvimopan interactions, 5 are rated major — including this one.
Worried about symptoms right now? Contact your pharmacist or prescriber, or call Poison Control at 1-800-222-1222 (US). Call 911 for an emergency.
Onset
rapid
Evidence
established
Severity
Major

What happens

Decreased opioid efficacy and precipitation of opioid withdrawal

Interaction Deep Dive

Concomitant use of morphine and an opioid antagonist should be avoided as this interaction may precipitate withdrawal symptoms or reduce the efficacy of morphine. Opioid antagonists should not be used in the absence of clinically significant respiratory depression, and should be used with caution in patients with known or suspected opioid physical dependence. If coadministration is required, use with caution and monitor the patient until spontaneous respiratory is reestablished. Morphine will continue to be released adding to the morphine load for 24 to 48 hours after ingestion, prolonging the need for monitoring123.

Why it happens (mechanism)

Competitive binding at opioid receptors

Common questions

Can I take Alvimopan and Morphine Sulfate Liposome together?

Decreased opioid efficacy and precipitation of opioid withdrawal Always confirm with your pharmacist or prescriber before making any change.

How serious is the Alvimopan and Morphine Sulfate Liposome interaction?

It is rated major. Potentially serious — often needs a change or close monitoring.

How quickly could this interaction happen?

The documented onset is "rapid". Effects can appear quickly, often within about 24 hours of combining the drugs.

How strong is the evidence for this interaction?

The evidence is graded "established". Well documented — supported by controlled studies or strong clinical data.

Questions for your pharmacist

  • Does my dose of Alvimopan or Morphine Sulfate Liposome 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)

  1. Product Information: AVINZA(R) oral extended release capsules, morphine sulfate oral extended release capsules. Pfizer Inc (per FDA), New York, NY, 2014. DailyMed
  2. Product Information: MS CONTIN(R) oral extended release tablets, morphine sulfate oral extended release tablets. Purdue Pharma L.P. (per FDA), Stamford, CT, 2014. DailyMed
  3. Product Information: KADIAN(R) oral extended-release capsules, morphine sulfate oral extended-release capsules. Actavis Pharma, Inc. (per FDA), Parsippany, NJ, 2014. DailyMed
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Morphine Sulfate Liposome

Keep reading about Morphine Sulfate Liposome

All Morphine Sulfate Liposome interactions (72)
Also serious with: Linezolid Injection Palonosetron Injection Naloxone Midazolam Injection
Alvimopan

Keep reading about Alvimopan

All Alvimopan interactions (5) Alvimopan drug information
Also serious with: Morphine Naldemedine Naloxegol Morphine Injection
Beyond drug–drug

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:

Alvimopan + Activated Charcoal St. John's Wort Bitter Melon Black Pepper Bulbine Natalensis Cannabis Coffee Charcoal Danshen + 46 more

major · moderate · minor — check everything you take with our drug–supplement interaction checker.

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This information is for education, not a substitute for professional medical advice. Do not start, stop, or change any medication without talking to your pharmacist or prescriber.