Acarbose and Methylene Blue: Interaction Details
AI-assisted, pharmacist-reviewed · AI content regenerated Jul 11, 2026 · Source data updated Jul 10, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Methylene Blue
Acarbose
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.
Methylene blue acts like a mild MAOI (a type of drug that affects certain brain and body chemicals), and acarbose is a diabetes medicine that helps lower your blood sugar after meals. When these two are used together, your blood sugar may drop lower than expected. That means you could feel shaky, sweaty, dizzy, confused, or very hungry.
The good news is this is very manageable. Your care team can watch your blood sugar more closely and adjust your diabetes medicine if needed. Please don't stop or change either medicine on your own. Just let your pharmacist or doctor know you're taking both, and ask them how to check for low blood sugar.
Effect: Additive glucose-lowering, increased risk of hypoglycemia. Methylene blue has MAOI activity; MAOIs can potentiate hypoglycemic agents (proposed hyperinsulinemia in type 2 patients with retained insulin secretion). Neither agent is affected via a prodrug pathway here; the interaction is pharmacodynamic.
- Direction: Increased effect of acarbose (enhanced hypoglycemic response)
- Onset: Rapid
- Evidence: Probable; mechanism not fully established
- Management: Closely monitor blood glucose when methylene blue is initiated or discontinued. Doses of acarbose (or insulin) may need reduction, individualized to the patient; discontinuation of one agent may occasionally be warranted.
What happens
An increased risk of hypoglycemia
Interaction Deep Dive
Certain MAOIs used alongside hypoglycemic drugs can enhance the blood glucose lowering action of those agents 23. In type 2 diabetics who still retain the ability to secrete insulin, MAOIs may produce hyperinsulinemia 7. When an MAOI is either introduced or withdrawn in a patient taking a hypoglycemic agent, blood glucose should be monitored closely. Reduced doses of insulin or oral hypoglycemic agents might be required 12, or it may be necessary to discontinue one of the interacting drugs 4.
Why it happens (mechanism)
Unknown
How to manage this interaction
Keep taking both medicines exactly as prescribed unless your care team tells you otherwise. Here's what a team typically does:
- Monitors blood sugar more closely, especially right after methylene blue is started or stopped.
- Adjusts and individualizes your diabetes medicine dose if your sugars run low.
- In some cases, they may choose to change one of the medicines.
Learn the signs of low blood sugar (shakiness, sweating, dizziness, confusion, hunger) and know how to treat it. Because acarbose blocks how you absorb table sugar, ask your pharmacist which fast sugar source (such as glucose tablets) to use if you go low. Raise any low readings with your pharmacist or prescriber.
Management is individual — confirm any change with your pharmacist or prescriber.
Literature reports
2 reports — tap to read
a) Drugs classified as MAOIs may potentiate the blood glucose lowering action of hypoglycemic agents. The suggested mechanism involved MAOI interference with the homeostatic adrenergic reaction to hypoglycemia 5, although this mechanism has not been verified 6. MAOIs seem to produce hyperinsulinemia 7.
b) Administration of selegiline (a selective MAO-B inhibitor) resulted in severe hypoglycemia in a 70-year old man who had Parkinson's disease. This hypoglycemia occurred together with hyperinsulinemia and continued for one week following discontinuation of selegiline 8.
Common questions
Can I take Acarbose and Methylene Blue together?
Combining methylene blue (which acts like an MAOI) with acarbose can push your blood sugar too low, so monitor closely and ask your care team about adjusting your diabetes dose. If you use acarbose, glucose tablets work better than table sugar to treat a low. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Acarbose and Methylene Blue interaction?
It is rated moderate. Can be significant — usually manageable with 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 is the Acarbose and Methylene Blue interaction managed?
Keep taking both medicines exactly as prescribed unless your care team tells you otherwise. Here's what a team typically does: Monitors blood sugar more closely, especially right after methylene blue is started or stopped. Adjusts and individualizes your diabetes medicine dose if your sugars run low. In some cases, they may choose to change one of the medicines. Learn the signs of low blood sugar… Management is individual — always follow your own care team's guidance.
How strong is the evidence for this interaction?
The evidence is graded "probable". Good supporting evidence, though not definitively proven.
From our Q&A
Real reader questions about these medications, each personally answered by our pharmacist:
Questions for your pharmacist
- Does my dose of Acarbose or Methylene Blue 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 anything you'd monitor while I'm on both?
References (8)
- Product Information: TOUJEO(R) subcutaneous injection, insulin glargine subcutaneous injection. sanofi-aventis (per manufacturer), Bridgewater, NJ, 2015. DailyMed
- Product Information: AMARYL(R) oral tablets, glimepiride oral tablets. Sanofi-Aventis U.S. LLC (per FDA), Bridgewater, NJ, 2013. DailyMed
- Product Information: Starlix(R) oral tablets, nateglinide oral tablets. Novartis Pharmaceuticals Corporation (per FDA), East Hanover, NJ, 2011. DailyMed
- Product Information: ZYVOX(R) intravenous injection, oral tablets suspension, linezolid intravenous injection, oral tablets suspension. Pfizer Inc. (per FDA), New York, NY, 2013. DailyMed
- Cooper AJ & Ashcroft G: Modification of insulin and sulfonylurea hypoglycemia by monoamine-oxidase inhibitor drugs. Diabetes 1967; 16:272-274. PubMed
- Adnitt PI: Hypoglycemic action of monoamineoxidase inhibitors (MAOI'S). Diabetes 1968; 17:628-633. PubMed
- Bressler R, Vargas-Cord M, & Lebovitz HE: Tranylcypromine: a potent insulin secretagogue and hypoglycemic agent. Diabetes 1968; 17:617-624. PubMed
- Rowland MJ, Bransome ED Jr. & Hendry LB: Hypoglycemia caused by selegiline, an antiparkinsonian drug: can such side effects be predicted?. J Clin Pharmacol 1994; 34:80-85. DOI
Keep reading about Methylene Blue
Keep reading about Acarbose
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