Monoamine oxidase inhibitors (MAOIs) are a class of drugs that inhibit the activity of one or both monoamine oxidase enzymes: monoamine oxidase A (MAO-A) and monoamine oxidase B (MAO-B).
They are best known as highly efficacious anti-depressants, as well as effective therapeutic agents for panic disorder and social phobia.
They are particularly effective in treatment-resistant depression and atypical depression.
They are also used in the treatment of Parkinson's disease and several other disorders.

Reversible inhibitors of monoamine oxidase A (RIMAs) are a subclass of MAOIs that selectively and reversibly inhibit the MAO-A enzyme.
RIMAs are used clinically in the treatment of depression and dysthymia.
 Due to their reversibility, they are safer in single-drug overdose than the older, irreversible MAOIs, and weaker in increasing the monoamines important in depressive disorder.
RIMAs have not gained widespread market share in the United States.

New research into MAOIs indicates that much of the concern over their supposed dangerous dietary side effects stems from misconceptions and misinformation, and that they are still underutilized despite demonstrated efficacy.
New research also questions the validity of the perceived severity of dietary reactions, which has been based on outdated research.
Despite this, many psychiatrists, who have little or no knowledge of and experience with monoamine oxidase inhibitors (and are thus unaware of their significant benefits), still reserve them as a last line of treatment, used only when other classes of antidepressant drugs (for example selective serotonin reuptake inhibitors and tricyclic antidepressants) have failed.
Monoamine oxidase inhibitors (MAOIs) are a class of drugs that inhibit the activity of one or both monoamine oxidase enzymes: monoamine oxidase A (MAO-A) and monoamine oxidase B (MAO-B). They are best known as highly efficacious anti-depressants, as well as effective therapeutic agents for panic disorder and social phobia. They are particularly effective in treatment-resistant depression and atypical depression. They are also used in the treatment of Parkinson's disease and several other disorders.
Reversible inhibitors of monoamine oxidase A (RIMAs) are a subclass of MAOIs that selectively and reversibly inhibit the MAO-A enzyme. RIMAs are used clinically in the treatment of depression and dysthymia.  Due to their reversibility, they are safer in single-drug overdose than the older, irreversible MAOIs, and weaker in increasing the monoamines important in depressive disorder. RIMAs have not gained widespread market share in the United States. 
New research into MAOIs indicates that much of the concern over their supposed dangerous dietary side effects stems from misconceptions and misinformation, and that they are still underutilized despite demonstrated efficacy. New research also questions the validity of the perceived severity of dietary reactions, which has been based on outdated research. Despite this, many psychiatrists, who have little or no knowledge of and experience with monoamine oxidase inhibitors (and are thus unaware of their significant benefits), still reserve them as a last line of treatment, used only when other classes of antidepressant drugs (for example selective serotonin reuptake inhibitors and tricyclic antidepressants) have failed.
Monoamine oxidase inhibitor