MAO (Monoamine Oxidase) inhibitors are a type of antidepressant medication. They are a type of mood elevator that slows down the metabolism of catecholamines, thus preserving them. It is suspected that both MAO inhibitors and tricyclic antidepressants may not only relieve the depression but may also raise the pain threshold. They are occasionally used for patients with difficult headache problems.

Headache patients taking MAO inhibitors must be very careful to avoid foods containing tyramine and all alcoholic beverages since a blood pressure crisis may arise.