Prozac is a medicine for treating depression. Alternatively known as fluoxetine, Prozac alters unstable brain chemicals in depressed people. Prozac is mostly used to cure MDD (major depressive disorder), obsessive compulsive disorder (OCD), eating disorders such as panic disorder and bulimia nervosa. Sometimes the doctor will combine Prozac with another drug (mainly Olanzapine) to tackle manic depression that is triggered by bipolar disorder.