USMLE

MAOIs

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Mental Health Drugs
  1. Tricyclic Antidepressants
  2. SSRIs
  3. SNRIs
  4. Benzodiazepines
  5. Barbiturates
  6. Typical Antipsychotics
  7. Atypical Antipsychotics
  8. Extrapyramidal Symptoms
  9. Lithium
  10. MAOIs
  11. Bupropion
  12. Buspirone
  13. Trazodone
  14. Zolpidem
  15. Amphetamines

Summary

MAOIs are a class of antidepressants and include the drugs isocarboxazid, phenelzine, and tranylcypromine. These drugs are used to treat depression, although they are not first-line treatments due to their side effects and dangerous food and drug interactions. Notably, MAOIs can cause a hypertensive crisis, especially if patients consume foods containing tyramine, like wine, cheese, and processed meats. MAOIs can also cause serotonin syndrome, a life-threatening condition resulting from overload of serotonin signaling. As such, MAOIs should not be given within 14 days of taking any other serotonin-altering drug.

Key Points

  • Key Drugs
    • Isocarboxazid
    • Phenelzine
    • Tranylcypromine
    • Selegiline
    • Rasagiline
    • Mechanism
      • Antidepressant
        • Inhibits the enzyme monoamine oxidase, thus increasing norepinephrine, serotonin, dopamine, and epinephrine levels in the brain.
    • Clinical Use
      • Depression
        • Because of severe adverse reactions of drug/food interactions, MAOIs are generally only used if other medications have been proved ineffective in treatment
      • Parkinson’s Disease
        • Selegiline and Rasagiline only (MAO-B inhibitors)
    • Side Effects and Adverse Reactions
      • Hypertensive Crisis
        • Extremely high blood pressure that can lead to stroke, often accompanied by symptoms such as headache, tachycardia, neck stiffness, etc.
        • Avoid foods containing tyramine as eating them can lead to a hypertensive crisis
          • Found in aged cheese, processed meats, wine, yogurt, pickled foods, avocados, chocolate, etc.
        • Hypertensive crisis may also occur with concurrent use of vasoconstrictors and cold medications that contain phenylephrine and pseudoephedrine
        • Closely monitor blood pressure and tell patient to report any signs of a hypertensive crisis
        • Educate patient to consult with provider before taking over the counter medications, as MAOIs have several drug interactions
      • Serotonin Syndrome
        • Symptoms include agitation, restlessness, confusion, tachycardia, hypertension, muscle rigidity
        • MAOIs should be withdrawn 14 days before starting an SSRI or TCA (and vice versa)
          • Concurrent use with other serotonin altering medications increases risk for serotonin syndrome
      • Hypoglycemia
        • MAOIs can increase the hypoglycemic effect of insulin and oral diabetic medications
      • Orthostatic hypotension
      • Anticholinergic effects