MAO-B Inhibitors

Antiparkinson Agents

Selegiline

• Nonselective inhibition of monoamine oxidase → ↓ breakdown of epinephrine, norepinephrine, serotonin, and dopamine → ↑ levels of epinephrine, norepinephrine, serotonin, and dopamine

• Selegiline: selective MAO-B inhibitor → mainly ↓ breakdown of dopamine → ↑ levels of dopamine

• Major depressive disorder (third- or fourth-line therapy): particularly effective treatment for atypical depression

• Parkinson disease: selegiline (as an adjunct to carbidopa-levodopa)

• Anxiety

• CNS stimulation

• Sexual dysfunction

• Orthostatic hypotension

• Weight gain

• Hypertensive crisis with ingestion of foods containing tyramine

  • Examples: aged cheeses, smoked/cured meats, alcoholic beverages (especially beer and red wine), dried fruits, fava beans, chocolate

  • Tyramine stimulates the sympathetic nervous system by releasing other neurotransmitters, such as noradrenaline, from vesicles into the synaptic cleft.

risk of serotonin syndrome if used concomitantly with other serotonergic drugs, including linezolid, SSRIs, TCAs, meperidine, dextromethorphan, and St. John’s wort

• Before starting new serotonergic drugs or ceasing dietary restrictions (e.g., foods containing tyramine), MAOI therapy has to be stopped for at least 2 weeks.

• Rarely used due to poor side-effect profile

• For the treatment of depression, selegiline is available as a transdermal patch (the oral form is only used for Parkinson disease).