Drug Interaction Report

Methylene Blue and Fentanyl Transdermal Patch: Interaction Details

A pharmacist-reviewed analysis of the Methylene Blue and Fentanyl Transdermal Patch interaction: the documented clinical effects, severity rating, onset, mechanism, and management considerations, with cited references throughout.

AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature

Methylene Blue

Provayblue
+

Fentanyl Transdermal Patch

Duragesic®
Dr. Brian Staiger, PharmD, BCPS
Medically reviewed by
Dr. Brian Staiger, PharmD, BCPS
Updated Aug 8, 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 45 documented Methylene Blue interactions, 24 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
unspecified
Evidence
theoretical
Severity
Major

What happens

Potentiation of opioid effects and an increased risk of serotonin syndrome

Interaction Deep Dive

FentaNYL should not be used during or within 14 days following the administration of an MAOI as this may lead to severe and unpredictable potentiation of opioid analgesic effects1. If concomitant use is required, appropriate monitoring is recommended and vasodilators and beta-blockers should be readily available 4. Additionally, fentaNYL is a proserotonergic, synthetic piperidine opioid and has been associated with serotonin syndrome when coadministered with MAOIs. If possible, consider replacing serotonergic opioids (eg, fentaNYL) with non-serotonergic opioids (eg, morphine) 3. If concomitant use is necessary, monitor patients for symptoms of serotonin syndrome. If serotonin syndrome develops, discontinue the offending agents and provide supportive care therapy as necessary 2. If IV use of methylene blue is required, use the lowest possible dose and monitor for CNS effects for up to 4 hours after administration 5.

Why it happens (mechanism)

Additive serotonergic effects

Common questions

Can I take Methylene Blue and Fentanyl Transdermal Patch together?

Potentiation of opioid effects and an increased risk of serotonin syndrome Always confirm with your pharmacist or prescriber before making any change.

How serious is the Methylene Blue and Fentanyl Transdermal Patch 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.

From our Q&A

Real reader questions about these medications, each personally answered by our pharmacist:

Questions for your pharmacist

  • Does my dose of Methylene Blue or Fentanyl Transdermal Patch 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 (5)

  1. Product Information: Fentanyl citrate intravenous, intramuscular injection, fentanyl citrate intravenous, intramuscular injection. Hospira Inc (per FDA), Lake Forest, IL, 2023. DailyMed
  2. Boyer EW & Shannon M: The serotonin syndrome. N Eng J Med 2005; 352(11):1112-1120. PubMed
  3. Rastogi R, Swarm RA, & Patel TA: Case scenario: opioid association with serotonin syndrome: implications to the practitioners. Anesthesiology 2011; 115(6):1291-1298. PubMed
  4. Product Information: SUBLIMAZE(R) intravenous injection, intramuscular injection, fentanyl citrate intravenous injection, intramuscular injection. Akorn, Inc. (per DailyMed), Lake Forest, IL, 2012. DailyMed
  5. Product Information: PROVAYBLUE(R) intravenous injection, methylene blue intravenous injection. American Regent, Inc. (per FDA), Shirley, NY, 2023. DailyMed
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Methylene Blue

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All Methylene Blue interactions (45)
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Fentanyl Transdermal Patch

Keep reading about Fentanyl Transdermal Patch

All Fentanyl Transdermal Patch interactions (493) Fentanyl Transdermal Patch drug information
Also serious with: Ensitrelvir Samidorphan Safinamide Phenelzine
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:

Methylene Blue + Activated Charcoal Lithium 5-htp Acetyl-l-carnitine Ayahuasca Black Cohosh Black Seed Coffee Charcoal + 30 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.