Both drugs affect the serotonin transporter (like an SSRI) but also affect other serotonin receptors to relieve major depression. Serotonin and norepinephrine reuptake inhibitors (SNRIs) are among the newer types of antidepressant. As the name implies, they block the reuptake of both serotonin and norepinephrine.
Besides, what does a SNRI do?
Depression is associated with low levels of serotonin and norepinephrine. It is thought that SNRIs help treat depression by keeping up the levels of these two chemical messengers in your brain. They do this by stopping serotonin and norepinephrine from going back into the cells that released them.