Fluoxetine (brand name Prozac) belongs to the SSRI class of inhibitors; selective serotonin reuptake inhibitors. It does not inhibit the reuptake of norepinephrine and dopamine when used at a therapeutic dose (40mg-80mg), but can delay the reuptake of serotonin, which then results in serotonin remaining in the system for longer after it is released. Fluoxetine works by increasing the concentration of allopregnanolone circulating in the brain. Allopregnanolone is a GABAA receptor positive allosteric modulator.

Fluoxetine is used to treat a myriad of disorders, including bulimia nervosa, obsessive-compulsive disorder, panic disorder, major depressive disorder and premenstrual dysphoric disorder. It has also been prescribed in some cases for erectile dysfunction.

Adverse effects associated with fluoxetine include sexual dysfunction, a higher risk of suicide (this is negated in over 65’s, it has shown to lower the risk of suicide in this age group) and discontinuation syndrome, in which a patient has adverse effects upon coming off SSRI medications.