Isocarboxazid (Marplan, Marplon, Enerzer) is a non-selective, irreversible monoamine oxidase inhibitor (MAOI) of the hydrazine class used as an antidepressant. Along with

phenelzine Phenelzine, sold under the brand name Nardil, among others, is a non-selective and irreversible monoamine oxidase inhibitor (MAOI) of the hydrazine class which is primarily used as an antidepressant and anxiolytic. Along with tranylcypromine an ...

and tranylcypromine, it is one of only three classical MAOIs still available for clinical use in the treatment of psychiatric disorders in the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territori ...

, though it is not as commonly employed in comparison to the others. Isocarboxazid is primarily used to treat mood and anxiety disorders. It has also been investigated in the treatment of

schizophrenia Schizophrenia is a mental disorder characterized by continuous or relapsing episodes of psychosis. Major symptoms include hallucinations (typically hearing voices), delusions, and disorganized thinking. Other symptoms include social wit ...

Parkinson's disease Parkinson's disease (PD), or simply Parkinson's, is a long-term degenerative disorder of the central nervous system that mainly affects the motor system. The symptoms usually emerge slowly, and as the disease worsens, non-motor symptoms becom ...

and other

dementia Dementia is a disorder which manifests as a set of related symptoms, which usually surfaces when the brain is damaged by injury or disease. The symptoms involve progressive impairments in memory, thinking, and behavior, which negatively affe ...

-related disorders. Isocarboxazid, as well as other MAOIs, increase the levels of the monoamine neurotransmitters serotonin, dopamine,

norepinephrine Norepinephrine (NE), also called noradrenaline (NA) or noradrenalin, is an organic chemical in the catecholamine family that functions in the brain and body as both a hormone and neurotransmitter. The name "noradrenaline" (from Latin '' ad' ...

, epinephrine, melatonin, phenethylamine in the brain.Volz, Hanz-Peter. (November 1998) “Monoamine Oxidase Inhibitors A Perspective on Their Use in The Elderly” ''Biochemical Pharmacology'' (5) 341-352. Classical MAOIs, including isocarboxazid, are used only rarely due to prominent food and

drug interaction Drug interactions occur when a drug's mechanism of action is disturbed by the concomitant administration of substances such as foods, beverages, or other drugs. The cause is often the inhibition of the specific receptors available to the drug, ...

s and have been largely superseded by newer antidepressants such as the

selective serotonin reuptake inhibitor Selective serotonin reuptake inhibitors (SSRIs) are a class of drugs that are typically used as antidepressants in the treatment of major depressive disorder, anxiety disorders, and other psychological conditions. SSRIs increase the extracellul ...

s (SSRIs). The cause of the interactions is because MAOIs inhibit the

metabolism Metabolism (, from el, μεταβολή ''metabolē'', "change") is the set of life-sustaining chemical reactions in organisms. The three main functions of metabolism are: the conversion of the energy in food to energy available to run c ...

of dietary amines (e.g.,

tyramine Tyramine ( ) (also spelled tyramin), also known under several other names, is a naturally occurring trace amine derived from the amino acid tyrosine. Tyramine acts as a catecholamine releasing agent. Notably, it is unable to cross the blood ...

) and the monoamine neurotransmitters. In combination with other drugs that increase the levels of the monoamine neurotransmitters such as the SSRIs, or with certain foods high in dietary amines such as

aged cheese Cheese ripening, alternatively cheese maturation or affinage, is a process in cheesemaking. It is responsible for the distinct flavour of cheese, and through the modification of "''ripening agents''", determines the features that define many di ...

s, MAOIs can produce dangerous elevations of monoamine neurotransmitters resulting in potentially life-threatening syndromes such as

hypertensive crisis Severely elevated blood pressure (equal to or greater than a systolic 180 or diastolic of 120—sometimes termed malignant or accelerated hypertension) is referred to as a hypertensive crisis, as blood pressure at this level confers a high risk ...

and

serotonin syndrome Serotonin syndrome (SS) is a group of symptoms that may occur with the use of certain serotonergic medications or drugs. The degree of symptoms can range from mild to severe, including a potentiality of death. Symptoms in mild cases include high ...

References

{{Hydrazines Monoamine oxidase inhibitors Isoxazoles Hepatotoxins Hydrazides

See also

References