Fluvoxamine is used to treat obsessive-compulsive disorder (bothersome thoughts that won't go away and the need to perform certain actions over and over) and social anxiety disorder (extreme fear of interacting with others or performing in front of others that interferes with normal life). Fluvoxamine is in a class of medications called selective serotonin reuptake inhibitors (SSRIs). It works by increasing the amount of serotonin, a natural substance in the brain that helps maintain mental balance.