Fluoxetine 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. Prozac (fluoxetine) is an SSRI antidepressant used to treat depression, OCD, panic disorder, bulimia, and PMDD by boosting serotonin levels in the brain. Fluoxetine is a type of antidepressant called a selective serotonin reuptake inhibitor (SSRI). It's thought to work by increasing the level of serotonin (a chemical in the brain linked to mood). Fluoxetine (Prozac) is a prescription antidepressant used to treat depression, OCD, bulimia, panic disorder, and PMDD. Learn about uses, dosage, side effects, and warnings. Fluoxetine is an antidepressant and belongs to a group of medicines known as selective serotonin reuptake inhibitors (SSRIs). This medicine works by increasing the activity of a chemical called serotonin in the brain. This medicine is available only with your doctor's prescription. Fluoxetine, sold under the brand name Prozac, among others, is an antidepressant medication of the selective serotonin reuptake inhibitor (SSRI) class [2] used for the treatment of major depressive disorder, anxiety, obsessive–compulsive disorder (OCD), panic disorder, premenstrual dysphoric disorder, and bulimia nervosa. [2] Find patient medical information for Fluoxetine (Prozac, Sarafem, others) on WebMD including its uses, side effects and safety, interactions, pictures, warnings, and user ratings.