What are Noradrenergic and Specific Serotonergic Antidepressants (NaSSAs)?

Noradrenergic and specific serotonergic antidepressants (NaSSAs) are a relatively new class of antidepressants. They are thought to act by noradrenergic autoreceptor and heteroreceptor antagonism combined with specific serotonergic antagonism. This results in increases in both noradrenergic and specific serotonergic transmission.

How Noradrenergic and Specific Serotonergic Antidepressants (NaSSAs) Work

Depression is associated with reduced levels of monoamines in the brain. Noradrenergic and specific serotonergic antidepressants (NaSSAs), such as mirtazapine, have a dual mechanism of action that increases the concentration of 5-HT and noradrenaline in the synaptic cleft to within the normal range. NaSSAs bind to and inhibit both noradrenaline a2-autoreceptors and noradrenaline a2-heteroeceptors. This action prevents the negative feedback effect of synaptic noradrenaline on 5-HT and noradrenaline neurotransmission, and neurotransmission sustained. NaSSAs also block 5-HT2 and 5-HT3 receptors on the post-synaptic membrane, which causes enhanced 5-HT1 mediated neurotransmission.

Examples of Noradrenergic and Specific Serotonergic Antidepressants (NaSSAs)

The only Noradrenergic and Specific Serotonergic Antidepressant (NaSSA) currently available is Remeron. The generic name for Remeron is Mirtazapine.

Side Effects of NaSSAs

NaSSAs are said to have fewer side-effects than tricyclic antidepressants and selective serotonin reuptake inhibitors (SSRIs) while being equally effective. In particular, it is said that the sexual dysfunction that is a relatively common side effect of SSRIs occurs significantly less often during treatment with NaSSAs. The main side effects noted during trials were somnolence, increased appetite, weight gain and dizziness.