Antidepressant
Antidepressant, medication used to treat depression, a mood disorder characterized by such symptoms as sadness, decreased appetite, difficulty sleeping, fatigue, and a lack of enjoyment of activities previously found pleasurable. While everyone experiences episodes of sadness at some point in their lives, depression is distinguished from this sadness when symptoms are present most days for a period of at least two weeks. Antidepressants are often the first choice of treatment for depression.
The first antidepressants, developed in the 1950s, are the tricyclic antidepressants (TCA) and the monoamine oxidase (MAO) inhibitors. TCAs block the reuptake of neurotransmitters into the presynaptic neurons, keeping the neurotransmitter in the synapse longer, and making more of the neurotransmitter available to the postsynaptic cell. TCAs include amitriptyline, doxepin, imipramine, nortriptyline, and desipramine.
MAO inhibitors decrease the rate at which neurotransmitters are broken down by the body so they are more available to interact with neurons. MAO inhibitors currently available in the United States include phenelzine and tranylcypromine.
Another group of antidepressants, known as selective serotonin reuptake inhibitors (SSRI), became available in 1987. SSRIs block the reuptake of the neurotransmitter serotonin into presynaptic neurons, thereby prolonging its activity. There are currently four SSRIs available for use in the United States: fluoxetine, sertraline, paroxetine, and fluvoxamine. Of this group, the best known is fluoxetine, commonly known by its brand name, Prozac.
Another antidepressant is venlafaxine, which works like TCAs but does not share their chemical structure, and it also causes different side effects. The antidepressant nefazodone prevents serotonin from binding to neighboring neurons at one specific binding site (serotonin can bind to neurons on many sites). It also weakly blocks the reuptake of serotonin.
The first antidepressants, developed in the 1950s, are the tricyclic antidepressants (TCA) and the monoamine oxidase (MAO) inhibitors. TCAs block the reuptake of neurotransmitters into the presynaptic neurons, keeping the neurotransmitter in the synapse longer, and making more of the neurotransmitter available to the postsynaptic cell. TCAs include amitriptyline, doxepin, imipramine, nortriptyline, and desipramine.
MAO inhibitors decrease the rate at which neurotransmitters are broken down by the body so they are more available to interact with neurons. MAO inhibitors currently available in the United States include phenelzine and tranylcypromine.
Another group of antidepressants, known as selective serotonin reuptake inhibitors (SSRI), became available in 1987. SSRIs block the reuptake of the neurotransmitter serotonin into presynaptic neurons, thereby prolonging its activity. There are currently four SSRIs available for use in the United States: fluoxetine, sertraline, paroxetine, and fluvoxamine. Of this group, the best known is fluoxetine, commonly known by its brand name, Prozac.
Another antidepressant is venlafaxine, which works like TCAs but does not share their chemical structure, and it also causes different side effects. The antidepressant nefazodone prevents serotonin from binding to neighboring neurons at one specific binding site (serotonin can bind to neurons on many sites). It also weakly blocks the reuptake of serotonin.
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