Isocarboxazid

**Semantic type:** Pharmacologic Substance

**Definition:** A hydralazine and monoamine oxidase (MAO) inhibitor with antidepressant activity. Isocarboxazid blocks the breakdown (oxidative deamination) of biogenic amines by inhibiting MAO, thereby increasing the concentrations of norepinephrine and 5-hydroxytrytamine (5-HT) at central aminergic receptors. These neurotransmitters are involved in sustaining mood and emotions. The down-regulation of central beta-adrenergic and serotonergic receptors by chronic inhibition of MAO may also contribute to the antidepressant effects seen by isocarboxazid. (NCI05)

**Synonyms:** - 3-Isoxazolecarboxylic Acid, 5-methyl-, 2-(phenylmethyl)hydrazide - ISOCARBOXAZID - Marplan - Ro 5-0831