Antidepressant

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Antidepressant medications are "mood-stimulating drugs used primarily in the treatment of affective disorders and related conditions. Several monoamine oxidase inhibitors are useful as antidepressants apparently as a long-term consequence of their modulation of catecholamine levels. The tricyclic compounds useful as antidepressive agents (tricyclic antidepressant) also appear to act through brain catecholamine systems. A third group (second-generation antidepressant agents) is a diverse group of drugs including some that act specifically on serotonergic systems."[1]

Mechanism of action

Depression may be due to the monoamine-deficiency hypothesis, which is a "deficiency in serotonin or norepinephrine neurotransmission in the brain."[2]

Classification

Tricyclic antidepressants

For more information, see: Tricyclic antidepressant.

Tricyclic antidepressants are "substances that contain a fused three-ring moiety and are used in the treatment of depression. These drugs block the uptake of norepinephrine and serotonin into axon terminals and may block some subtypes of serotonin, adrenergic, and histamine receptors. However the mechanism of their antidepressant effects is not clear because the therapeutic effects usually take weeks to develop and may reflect compensatory changes in the central nervous system."[3]

Heterocyclic antidepressants

Heterocyclic antidepressants include trazadone and bupropion, and more recently, mirtazapine and nefazadone which are based on trazadone[4]

Second-generation antidepressants

For more information, see: Second-generation antidepressant.

Second-generation antidepressants are a "structurally and mechanistically diverse group of drugs that are not tricyclics or monoamine oxidase inhibitors. The most clinically important appear to act selectively on serotonergic systems, especially by inhibiting serotonin reuptake."[5]

Monoamine oxidase inhibitors

Monoamine oxidase inhibitors are a "chemically heterogeneous group of drugs that have in common the ability to block oxidative deamination of naturally occurring monoamines".[6]

Adverse effects

Neuroleptic malignant syndrome

For more information, see: Neuroleptic malignant syndrome.

Serotonin syndrome

For more information, see: serotonin syndrome.

References

See also