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MAOI Toxicity 





  • Monoamine oxidase inhibitors (MAOIs) are used to treat multiple psychiatric disorders (including treatment-resistant depression) & Parkinson's disease

  • Thought to ↑ dopaminergic, noradrenergic, and serotonergic neurotransmission (MAO B

  • Inhibit breakdown of tyramine (can trigger release of norepi) --> may precipitate hypertensive crisis in setting of drug-food (ex aged cheeses, cured meats) or drug-drug interactions




  • Risk of Serotonin Syndrome if combined w/ other serotonergic Rx

    • Avoid serotonergic analgesics (fentanyl, meperidine, tramadol); morphine ok

  • Risk of hypertensive crisis

    • Avoid indirect sympathomimetics, caution w/ direct agents

    • Avoid cocaine

  • Overdose can be fatal; signs & symptoms may not appear for up to 12 hrs

    • ↑ HR, irregular pulse, ↑ or ↓ BP, vascular collapse, resp depression/failure, hyperpyrexia, diaphoresis +/- cool clammy skin, agitation, coma, convulsions, dilated pupils, trismus


  • Stopping irreversible MAOIs >2 weeks preop to ↓ risk of serotonin syndrome/hypertensive crisis vs potential to exacerbate depression/suicidal ideation

    • MAOIs need to be tapered to avoid discontinuation symptoms


  • See Serotonin Syndrome

  • See Hypertension

  • Overdose

    • Supportive measures prn

    • Urine acidification may accelerate excretion

    • Consider dialysis

    • Restrict dietary tyramine x2 weeks​​


  • Sub Laban T, Saadabadi A. Monoamine Oxidase Inhibitors (MAOI) [Updated 2022 Jul 19]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-.  Available from:

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