The serotonin-norepinephrine reuptake inhibitor, or SNRI, class (venlafaxine and duloxetine) is notable for a dual mechanism of action: increasing the levels of the neurotransmitters serotonin and norepinephrine by inhibiting their reabsorption into cells in the brain. As with other medications, side effects may occur, including stomach upset, insomnia, headache, sexual dysfunction, weight gain and minor increase in blood pressure. These medications are considered as effective as SSRIs, so they are also considered a first-line treatment for the treatment of anxiety disorders, but not for obsessive compulsive disorder ,where SSRIs are the preferred first line treatment.
