Fluoxetine drug crystals. Polarized light micrograph of crystals of the drug fluoxetine hydrochloride, a selective serotonin-reuptake inhibitor antidepressant. Trade names for the drug include Prozac, Sarafem and Symbyax. It enhances the action of the neurotransmitter serotonin, improving mood and decreasing anxiety. It is used to treat a wide range of disorders, including major depressive disorder, obsessive compulsive disorder and panic disorder. It is on the World Health Organization's List of Essential Medicines. Field of view size: 297 x 445 micrometres.