Fluoxetine is used to treat depression, obsessive-compulsive disorder (bothersome thoughts that won't go away and the need to perform certain actions over and over), some eating disorders, and panic attacks (sudden, unexpected attacks of extreme fear and worry about these attacks). Fluoxetine is also used to relieve the symptoms of premenstrual dysphoric disorder, including mood swings, irritability, bloating, and breast tenderness. It is also used along with olanzapine (Zyprexa) to treat depression that did not respond to other medications and episodes of depression in people with bipolar I disorder (manic-depressive disorder; a disease that causes episodes of depression, episodes of mania, and other abnormal moods). Fluoxetine is in a class of medications called selective serotonin reuptake inhibitors (SSRIs). It works by increasing the amount of serotonin, a natural substance in the brain that helps maintain mental balance.

Fluoxetine comes as a capsule, a tablet, a delayed-release (releases the medication in the intestine) capsule, and a solution (liquid) to take by mouth. Fluoxetine may be taken with or without food. Fluoxetine capsules, tablets, and liquid are usually taken once a day in the morning or twice a day in the morning and at noon. Fluoxetine delayed-released capsules are usually taken once a week. Take fluoxetine at around the same time(s) every day. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take fluoxetine exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.

Sleep, energy, or appetite may show some improvement within the first 1-2 weeks. Improvement in these physical symptoms can be an important early signal that the medication is working. Depressed mood and lack of interest in activities may need up to 6-8 weeks to fully improve.

• Symptoms of your condition that bother you most
• If you have thoughts of suicide or harming yourself 
• Medications you have taken in the past for your condition, whether they were effective or caused any adverse effects
• If you experience side effects from your medications, discuss them with your provider. Some side effects may pass with time, but others may require an adjustment in the medication. 
• Any other psychiatric or medical problems you have, including a history of bipolar disorder 
• All other medications you are currently taking and any medication allergies you have. This will help your prescriber assess for potential drug interactions.
• Other non-medication treatment you are receiving (such as psychotherapy (i.e., talk therapy) or substance abuse treatment). Your provider can explain how these different treatments work with the medication. 
• If you are pregnant, plan to become pregnant, or are breastfeeding 
• If you drink alcohol or use drugs

Headache, nausea, diarrhea, dry mouth, increased sweating, feeling nervous, restless, fatigue, or having trouble sleeping (insomnia). These will often improve over the first week or two as you continue to take the medication. Sexual side effects, such as problems with orgasm or ejaculatory delay often do not diminish over time.