What are the medications classified as Monoamine Oxidase (MAO) inhibitors?

Monoamine Oxidase Inhibitors (MAOIs)

The medications classified as Monoamine Oxidase Inhibitors (MAOIs) include selegiline, phenelzine, linezolid, isocarboxazid, and tranylcypromine. 1

Types of MAOIs

• Irreversible, Non-selective MAOIs:

  • Phenelzine 2
  • Tranylcypromine 3
  • Isocarboxazid 4, 5

• Selective MAOIs:

  • Selegiline (MAO-B selective) 4, 6
  • Moclobemide (reversible MAO-A selective) 6, 5

• Other medications with MAO inhibiting properties:

  • Linezolid (antibiotic with MAO inhibiting properties) 4, 3

Clinical Uses

• MAOIs are primarily used for treatment of depression, particularly treatment-resistant depression and atypical depression 4, 5
• They are also recommended for certain anxiety disorders with high levels of anxiety 4
• Selegiline is used in the treatment of Parkinson's disease 6, 5

Important Drug Interactions

• Contraindicated combinations with MAOIs:
  • Other MAOIs - risk of hypertensive crisis 4, 2
  • SSRIs and SNRIs - risk of serotonin syndrome 4, 7, 2
  • Tricyclic antidepressants - risk of serotonin syndrome 4, 2
  • Opioids (especially meperidine, tramadol, methadone, fentanyl) - risk of serotonin syndrome and hypertensive crisis 1, 2, 3
  • Stimulants (amphetamines, methylphenidate) - risk of hypertensive crisis 2, 3
  • Sympathomimetic drugs (pseudoephedrine, phenylephrine) - risk of hypertensive crisis 2, 8
  • Dextromethorphan - risk of serotonin syndrome 2, 8

Dietary Restrictions

• Patients taking MAOIs must avoid foods high in tyramine due to risk of hypertensive crisis 3, 8
• Foods to avoid include:
  • Aged cheeses 3
  • Fermented, aged, or smoked meats (salami, pepperoni) 2, 3
  • Pickled herring 2, 3
  • Broad bean pods (fava beans) 3
  • Tap beer and unpasteurized beers 3
  • Concentrated yeast extract (Marmite) 3
  • Sauerkraut and most soybean products 3

Safety Considerations

• When switching to or from MAOIs, adequate washout periods are essential (typically 2 weeks, 5 weeks for fluoxetine) 4, 3
• Patients on MAOIs should be educated about:
  • Avoiding over-the-counter medications without consulting healthcare providers 4, 8
  • Recognizing signs of serotonin syndrome and hypertensive crisis 4, 8
  • Informing all healthcare providers about MAOI use 4

Common Pitfalls to Avoid

• Failure to maintain adequate washout periods when switching between MAOIs and other antidepressants can lead to serotonin syndrome 4
• Not considering over-the-counter medications and supplements as potential contributors to adverse reactions 7, 8
• Underestimating the importance of dietary restrictions with irreversible MAOIs 3, 8
• Not recognizing that certain antibiotics like linezolid have MAO inhibiting properties 4, 3

Monitoring Recommendations

• Monitor for signs of serotonin syndrome: mental status changes, neuromuscular hyperactivity, and autonomic instability 7
• Monitor blood pressure, especially when initiating therapy or changing doses 4, 6
• Be vigilant for drug interactions when prescribing additional medications to patients on MAOIs 8