Monoamine oxidase Health Dictionary

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Monoamine Oxidase: From 1 Different Sources

(MAO) an enzyme that catalyses the oxidation of a large variety of monoamines, including adrenaline, noradrenaline, and serotonin. Monoamine oxidase is found in most tissues, particularly the gastrointestinal tract and nervous system, and exists in two forms in humans: monoamine oxidase A primarily breaks down noradrenaline and serotonin, whereas monoamine oxidase B primarily degrades dopamine. Drugs that act as inhibitors of monoamine oxidase A may be used in the treatment of depression (see MAO inhibitor); monoamine oxidase B inhibitors are used to treat Parkinson’s disease.
Health Source: Oxford | Concise Colour Medical Dictionary
Author: Jonathan Law, Elizabeth Martin

Monoamine Oxidase Inhibitors (maois)

These are drugs that destroy, or prevent the action of, monoamine oxidase (MAO). Monoamines, which include NORADRENALINE and tyramine, play an important part in the metabolism of the BRAIN, and there is some evidence that excitement is due to an accumulation of monoamines in the brain. MAO is a naturally occurring ENZYME which is concerned in the breakdown of monoamines. MAOIs were among the earliest ANTIDEPRESSANT DRUGS used, but they are now used much less than tricyclic and related antidepressants, or SELECTIVE SEROTONIN-REUPTAKE INHIBITORS (SSRIS) and related antidepressants, because of the dangers of dietary or drug interactions – and because MAOIs are less e?ective than these two groups.

An excessive accumulation of monoamines can induce a dangerous reaction characterised by high blood pressure, palpitations, sweating and a feeling of su?ocation. Hence the care with which MAOI drugs are administered. What is equally important, however, is that in no circumstances should a patient receiving any MAOI drug eat cheese, yeast preparations such as Marmite, tinned ?sh, or high game. The reason for this ban is that all these foodstu?s contain large amounts of tyramine which increases the amount of certain monoamines such as noradrenaline in the body. (See MENTAL ILLNESS.)

There are also certain drugs, such as AMPHETAMINES and PETHIDINE HYDROCHLORIDE, which must not be taken by a patient who is receiving an MAOI drug. The MAOIs of choice are phenelzine or isocarboxazid because their stimulant effects are less than those of other MAOIs, making them safer.... monoamine oxidase inhibitors (maois)

Monoamine Oxidase Inhibitors

Also known as MAOIs, one of the 3 main types of antidepressant drug.

They work by preventing the breakdown of certain neurotransmitters by the enzyme monoamine oxidase.

The increased levels of neurotransmitters that result are associated with improved mood.

Common drugs include phenelzine and isocarboxazid.

All MAOIs interact with certain other drugs and foods such as cheese and red wine; but moclobemide is known as a reversible , which makes the adverse reactions less likely to occur.... monoamine oxidase inhibitors

Oxidase

n. see oxidoreductase.... oxidase

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