How MAOIs work

Antidepressants such as MAOIs ease depression by affecting chemical messengers (neurotransmitters) used to communicate between brain cells. Like most antidepressants, MAOIs work by ultimately effecting changes in the brain chemistry that are operational in depression.

An enzyme called monoamine oxidase is involved in removing the neurotransmitters norepinephrine, serotonin and dopamine from the brain. MAOIs prevent this from happening, which makes more of these brain chemicals available to effect changes in both cells and circuits that have been impacted by depression.

MAOIs also affect other neurotransmitters in the brain and digestive system, causing side effects. MAOIs are sometimes used to treat conditions other than depression, such as Parkinson's disease.