Fluoxetine (also known by the tradenames Prozac, Sarafem, Ladose and Fontex, among others) is an antidepressant of the selective serotonin reuptake inhibitor (SSRI) class. Fluoxetine was first documented in 1974 by scientists from Eli Lilly and Company.^[6] It was presented to the U.S. Food and Drug Administration in February 1977, with Eli Lilly receiving final approval to market the drug in December 1987. Fluoxetine went off-patent in August 2001.^[7]

Fluoxetine is approved in the US for the treatment of major depression (including paediatric depression), obsessive-compulsive disorder (in both adult and paediatric populations), bulimia nervosa, panic disorder and premenstrual dysphoric disorder.^[8] In addition, fluoxetine is used to treat trichotillomania if cognitive behaviour therapy is unsuccessful.^[9] In combination with the atypical antipsychotic olanzapine it is known by a few brand names,^{[note 1]} including its US brand name Symbyax, which is approved for the treatment of depressive episodes as part ofbipolar I disorder and in the treatment of treatment-resistant depression.

Despite the availability of newer agents, fluoxetine remains extremely popular. In 2010, over 24.4 million prescriptions for generic formulations of fluoxetine were filled in the United States alone,^[10] making it the third most prescribed antidepressant after sertraline (SSRI; became generic in 2006) and citalopram (SSRI; became generic in 2003).^[10] In 2011, 6 million prescriptions for fluoxetine were handed out in the UK.