Fluoxetine, sold under the brand names Prozac and Sarafem among others, is an antidepressant of the selective serotonin reuptake inhibitor (SSRI) class. It is used for the treatment of major depressive disorder, obsessive–compulsive disorder (OCD), bulimia nervosa, panic disorder, and premenstrual dysphoric disorder. It may decrease the risk of suicide in those over the age of 65. It has also been used to treat premature ejaculation. Fluoxetine is taken by mouth.
Common side effects include trouble sleeping, sexual dysfunction, loss of appetite, dry mouth, rash, and abnormal dreams. Serious side effects include serotonin syndrome, mania, seizures, an increased risk of suicidal behavior in people under 25 years old, and an increased risk of bleeding. If stopped suddenly, a withdrawal syndrome may occur with anxiety, dizziness, and changes in sensation. It is unclear if it is safe in pregnancy. If already on the medication, it may be reasonable to continue during breastfeeding. Its mechanism of action is not entirely clear but believed to be related to increasing serotonin activity in the brain.
Fluoxetine was discovered by Eli Lilly and Company in 1972, and entered medical use in 1986. It is on the World Health Organization's List of Essential Medicines, the most effective and safe medicines needed in a health system. It is available as a generic medication. The wholesale cost in the developing world is between US$0.01 and US$0.04 per day as of 2014. In the United States, it costs about US$0.85 per day. In 2016 it was the 29th most prescribed medication in the United States with more than 23 million prescriptions.