Serotonin-norepinephrine reuptake inhibitos (SNRIs) are antidepressant medications that act upon neurotransmitters in the brain that affect a person’s mood. SNRIs are utilized in the treatment of depression and chronic pain. Related Definitions Psychologist Editor’s Top Picks Antidepressants: Definitive Guide Depression and Chronic Back Pain Trouble Swallowing Pills (Dysphagia)