Fluoxetine is also sometimes used to treat alcoholism, attention-deficit disorder, borderline personality disorder, sleep disorders, headaches, mental illness, posttraumatic stress disorder, Tourette's syndrome, obesity, sexual problems, and phobias. Talk to your doctor about the possible risks of using this medication for your condition. Prozac (fluoxetine) can cause insomnia, drowsiness, and less sex drive in some people. Review a list of common Prozac side effects, plus ways to manage them. How long does it take for Prozac (fluoxetine) to work? It takes at least four weeks for Prozac to work for depression and OCD but some people may feel the effects as soon as two weeks after taking it regularly. A psychiatrist-reviewed guide to fluoxetine (Prozac), an SSRI for depression, OCD, panic, and bulimia: how it works, side effects, and what to expect. Prozac (fluoxetine) is an SSRI antidepressant used to treat depression, OCD, panic disorder, bulimia, and PMDD by boosting serotonin levels in the brain. NHS information about the medicine fluoxetine, including what it's used for, who can take it, how to take it and side effects. Fluoxetine is taken by mouth. [2] Common side effects of fluoxetine include loss of appetite, nausea, diarrhea, headache, trouble sleeping, dry mouth, and sexual dysfunction. In some patients, sexual dysfunction may persist even after the drug is discontinued, a condition known as post-SSRI sexual dysfunction. [11] Find patient medical information for Fluoxetine (Prozac, Sarafem, others) on WebMD including its uses, side effects and safety, interactions, pictures, warnings, and user ratings Fluoxetine is an antidepressant and belongs to a group of medicines known as selective serotonin reuptake inhibitors (SSRIs). This medicine works by increasing the activity of a chemical called serotonin in the brain. This medicine is available only with your doctor's prescription. Fluoxetine (Prozac) is a prescription antidepressant used to treat depression, OCD, bulimia, panic disorder, and PMDD. Learn about uses, dosage, side effects, and warnings.