- Metabolism: Hepatic and rapid (by oxidation).
- Uses/Sources: May be used to treat major depressive disorder.
- Symptoms: Signs of overdose include severe anxiety, confusion, convulsions, cool clammy skin, severe dizziness, severe drowsiness, fast and irregular pulse, fever, hallucinations, severe headache, high or low blood pressure, hyperactive reflexes, muscle stiffness, respiratory depression or failure, slowed reflexes, sweating, severe trouble in sleeping, and unusual irritability.
- Treatment: General supportive measures should be used, along with immediate gastric lavage or emetics. If the latter are given, the danger of aspiration must be borne in mind. An adequate airway should be maintained, with supplemental oxygen if necessary. The mechanism by which amine-oxidase inhibitors produce hypotension is not fully understood, but there is evidence that these agents block the vascular bed response. Thus it is suggested that plasma may be of value in the management of this hypotension. Administration of pressor amines such as levarterenol bitartrate may be of limited value (note that their effects may be potentiated by Isocarboxazid). Continue treatment for several days until homeostasis is restored. Liver function studies are recommended during the 4 to 6 weeks after recovery, as well as the time of overdosage.
- Route of Exposure: Well absorbed from the gastrointestinal tract.
Mechanism of Action
|Target Name||Mechanism of Action||References|
Amine oxidase [flavin-containing] A
Amine oxidase [flavin-containing] B
|Isocarboxazid works by irreversibly blocking the action of a chemical substance known as monoamine oxidase (MAO) in the nervous system. MAO subtypes A and B are involved in the metabolism of serotonin and catecholamine neurotransmitters such as epinephrine, norepinephrine, and dopamine. Isocarboxazid, as a nonselective MAO inhibitor, binds irreversibly to monoamine oxidase–A (MAO-A) and monoamine oxidase–B (MAO-B). The reduced MAO activity results in an increased concentration of these neurotransmitters in storage sites throughout the central nervous system (CNS) and sympathetic nervous system. This increased availability of one or more monoamines is the basis for the antidepressant activity of MAO inhibitors.||