MAOIs

• Monoamine oxidase inhibitors (MAOIs) are not prescribed as commonly as other types of antidepressants due to severe food and drug interactions
• Examples:

  • Reversible = moclobemide, selegiline, rasagiline
  • Irreversible = phenelzine, isocarboxazid, tranylcypromine
• MOA:

  • Inhibit monoamine oxidase = increase in amine neurotransmitters
• Indications:

  • Depression which is refractory to treatment
  • Social anxiety
  • Works well in patients with phobia, or atypical hypochondriacal or hysterical features
• Non-selective MAOIs e.g. phenelzine - used in treatment of atypical depression
• Contraindications and cautions:

  • Contraindicated in cerebrovascular disease, pheochromocytoma and in manic phases
  • Avoid concomitant use of other antidepressants
  • Avoid in pregnancy
  • Avoid in agitated patients
  • Use with caution in elderly patients and patients who experience severe hypertensive reactions to certain drugs and food
  • Use with caution in cardiovascular disease and diabetes
• Interactions:

  • Food and drinks with high tyramine content - mature cheese, pickled herring, hydrolysed meats, yeast, alcohol, pickles
  • Other antidepressants - risk of serotonin syndrome
  • Carbamazepine (and other antiepileptics)
• Side effects:

  • Common = dizziness and postural hypotension
  • Behavioural changes including agitation
  • Convulsions
  • GI disturbances
  • Deranged LFTs
• Eating food or drink high in tyramine whilst on an MAOI can cause a hypertensive reaction
• Counselling:

  • Dangerous reactions to food and drink - high tyramine content e.g. cheese, hydrolysed meats, pickled foods and alcohol. Advise patients to only eat fresh food and avoid food that is suspected of being stale or "going off" - this reaction can happen up to 2 weeks after stopping MAOI
  • Do not take another antidepressant at the same time