Acarbose and Isocarboxazid: 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
Isocarboxazid
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.
Isocarboxazid (Marplan) is an older antidepressant called an MAOI, and acarbose (Precose) helps lower your blood sugar. When they are taken together, the MAOI can add to acarbose's blood sugar lowering effect, so your sugar may drop too low (hypoglycemia). This can leave you feeling shaky, sweaty, dizzy, or confused, and it can happen fairly quickly.
The good news is that this is very manageable. Your care team can watch your blood sugar more closely and adjust your doses if needed. Keep taking both medicines as prescribed, and let your pharmacist or doctor know if you notice low blood sugar symptoms.
Effect: Additive glucose lowering, increased hypoglycemia risk when isocarboxazid (MAOI) is combined with acarbose.
- Mechanism: Not fully established; MAOIs may promote hyperinsulinemia in type 2 patients with retained insulin secretory capacity, augmenting the hypoglycemic response. Neither agent is metabolized as a prodrug relevant here.
- Direction: Increased effect of the hypoglycemic agent (PD interaction).
- Onset: Rapid. Evidence: Probable. Severity: Moderate.
- Management: Intensify blood glucose monitoring when initiating or discontinuing the MAOI. Antidiabetic dose may need reduction and individualization; occasionally discontinuation of one agent is warranted.
What happens
An increased risk of hypoglycemia
Interaction Deep Dive
When certain MAOIs are taken alongside hypoglycemic agents, the blood glucose lowering action of these agents may be enhanced 23. In patients with type 2 diabetes who retain the ability to secrete insulin, MAOIs can produce hyperinsulinemia 7. Blood glucose levels should be monitored closely whenever an MAOI is introduced or withdrawn in a patient already taking a hypoglycemic agent. It may be necessary to reduce doses of insulin or oral hypoglycemic agents 12, or alternatively to discontinue one of the interacting drugs 4.
Why it happens (mechanism)
Unknown
How to manage this interaction
This combination can lower blood sugar more than acarbose alone, so your care team will typically manage it proactively:
- Closer monitoring: Expect more frequent blood glucose checks, especially when the MAOI is started or stopped.
- Dose tailoring: Your acarbose (or other diabetes medicine) dose may need to be adjusted and individualized by your care team.
- Know the signs: Shakiness, sweating, dizziness, hunger, or confusion can mean low blood sugar.
Keep taking both medicines exactly as prescribed. Do not change or stop anything on your own. Bring your glucose readings to your pharmacist or prescriber and report any low sugar episodes so they can fine-tune your plan.
Management is individual — confirm any change with your pharmacist or prescriber.
Literature reports
2 reports — tap to read
a) MAOI agents can intensify the blood glucose lowering action of hypoglycemic medications. The suggested mechanism involved MAOI agents disrupting the homeostatic adrenergic response to hypoglycemia 5, although this mechanism was not confirmed 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 was associated with hyperinsulinemia and continued for one week following the discontinuation of selegiline 8.
Common questions
Can I take Acarbose and Isocarboxazid together?
Taking isocarboxazid with acarbose can push your blood sugar too low, so monitor closely and let your care team adjust your diabetes dose. Keep taking both as prescribed and report any low blood sugar symptoms. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Acarbose and Isocarboxazid 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 Isocarboxazid interaction managed?
This combination can lower blood sugar more than acarbose alone, so your care team will typically manage it proactively: Closer monitoring: Expect more frequent blood glucose checks, especially when the MAOI is started or stopped. Dose tailoring: Your acarbose (or other diabetes medicine) dose may need to be adjusted and individualized by your care team. Know the signs: Shakiness, sweating, dizzin… 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.
Questions for your pharmacist
- Does my dose of Acarbose or Isocarboxazid 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 Isocarboxazid
Keep reading about Acarbose
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