Fluoxetine is used to treat depression, panic attacks, obsessive compulsive disorder, a certain eating disorder (bulimia), and a severe form of premenstrual syndrome (premenstrual dysphoric disorder). This medication may improve your mood, sleep, appetite, and energy level and may help restore your interest in daily living. It may decrease fear, anxiety, unwanted thoughts, and the number of panic attacks. It may also reduce the urge to perform repeated tasks (compulsions such as hand-washing, counting, and checking) that interfere with daily living. Fluoxetine may lessen premenstrual symptoms such as irritability, increased appetite, and depression. It may decrease binging and purging behaviors in bulimia.
Read the Medication Guide provided by your pharmacist before you start using fluoxetine and each time you get a refill. If you have any questions, ask your doctor or pharmacist. Take this medication by mouth as directed by your doctor, usually once daily in the morning. If you are taking this medication twice a day, your doctor may direct you to take it in the morning and at noon. If you are taking fluoxetine for premenstrual problems, your doctor may direct you to take it every day of the month or just for the 2 weeks before your period through the first full day of your period. To help you remember, mark your calendar. If you are using the liquid form of this medication, measure the dose carefully using a special measuring device/spoon. Do not use a household spoon because you may not get the correct dose. The dosage is based on your medical condition and response to treatment. To reduce your risk of side effects, your doctor may direct you to start this medication at a low dose and gradually increase your dose. Follow your doctor's instructions carefully. Take this medication regularly to get the most benefit from it. To help you remember, take it at the same time each day. It is important to continue taking this medication as prescribed even if you feel well. Do not stop taking this medication without first consulting your doctor. Some conditions may become worse when the drug is abruptly stopped. Your dose may need to be gradually decreased. You should see some improvement in 1 to 2 weeks. It may take 4 to 5 weeks before you feel the full benefit. Tell your doctor if your condition does not improve or if it worsens.
See also Warning section. Nausea, drowsiness, dizziness, anxiety, trouble sleeping, loss of appetite, tiredness, sweating, or yawning may occur. If any of these effects persist or worsen, tell your doctor promptly. Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects. Tell your doctor right away if you have any serious side effects, including: unusual or severe mental/mood changes (such as agitation, unusual high energy/excitement, thoughts of suicide), easy bruising/bleeding, muscle weakness/spasm, shakiness (tremor), decreased interest in sex, changes in sexual ability, unusual weight loss. Get medical help right away if you have any very serious side effects, including: bloody/black/tarry stools, vomit that looks like coffee grounds, seizures, signs of kidney problems (such as change in the amount of urine), eye pain/swelling/redness, widened pupils, vision changes (such as seeing rainbows around lights at night, blurred vision). If you have diabetes, fluoxetine may affect your blood sugar levels. Monitor your blood sugar regularly and share the results with your doctor. Your doctor may need to adjust your medication, diet, and exercise when you start or stop fluoxetine. This medication may increase serotonin and rarely cause a very serious condition called serotonin syndrome/toxicity. The risk increases if you are also taking other drugs that increase serotonin, so tell your doctor or pharmacist of all the drugs you take (see Drug Interactions section). Get medical help right away if you develop some of the following symptoms: fast heartbeat, hallucinations, loss of coordination, severe dizziness, severe nausea/vomiting/diarrhea, twitching muscles, unexplained fever, unusual agitation/restlessness. Rarely, males may have a painful or prolonged erection lasting 4 or more hours. If this occurs, stop using this drug and get medical help right away, or permanent problems could occur. A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing. This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist. In the US - Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch. In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.
Store at room temperature away from light and moisture. Do not store in the bathroom. Keep all medications away from children and pets. Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company.
Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval. Fluoxetine can stay in your body for many weeks after your last dose and may interact with many other medications. Before using any medication, tell your doctor or pharmacist if you have taken fluoxetine in the previous 5 weeks. Some products that may interact with this drug include: other drugs that can cause bleeding/bruising (including antiplatelet drugs such as clopidogrel, NSAIDs such as ibuprofen, "blood thinners" such as warfarin). Taking MAO inhibitors with his medication may cause a serious (possibly fatal) drug interaction. Avoid taking MAO inhibitors (isocarboxazid, linezolid, methylene blue, moclobemide, phenelzine, procarbazine, rasagiline, safinamide, selegiline, tranylcypromine) during treatment with this medication. Most MAO inhibitors should also not be taken for 2 weeks before and at least 5 weeks after treatment with this medication. Ask your doctor when to start or stop taking this medication. This medication can slow down the removal of other medications from your body, which may affect how they work. Examples of affected drugs include pimozide, thioridazine, vinblastine, antiarrhythmics (such as propafenone, flecainide), tricyclic antidepressants (such as desipramine, imipramine), among others. Aspirin can increase the risk of bleeding when used with this medication. However, if your doctor has directed you to take low-dose aspirin for heart attack or stroke prevention (usually at dosages of 81-325 milligrams a day), you should continue taking it unless your doctor instructs you otherwise. The risk of serotonin syndrome/toxicity increases if you are also taking other drugs that increase serotonin. Examples include street drugs such as MDMA/"ecstasy," St. John's wort, certain antidepressants (including other SSRIs such as citalopram/paroxetine, SNRIs such as duloxetine/venlafaxine), tryptophan, among others. The risk of serotonin syndrome/toxicity may be more likely when you start or increase the dose of these drugs. Tell your doctor or pharmacist if you are taking other products that cause drowsiness including alcohol, marijuana (cannabis), antihistamines (such as cetirizine, diphenhydramine), drugs for sleep or anxiety (such as alprazolam, diazepam, zolpidem), muscle relaxants, and narcotic pain relievers (such as codeine). Check the labels on all your medicines (such as allergy or cough-and-cold products) because they may contain ingredients that cause drowsiness. Ask your pharmacist about using those products safely. This medication may interfere with certain medical/laboratory tests (including brain scan for Parkinson's disease), possibly causing false test results. Make sure laboratory personnel and all your doctors know you use this drug.
If someone has overdosed and has serious symptoms such as passing out or trouble breathing, call 911. Otherwise, call a poison control center right away. US residents can call their local poison control center at 1-800-222-1222. Canada residents can call a provincial poison control center. Symptoms of overdose may include: fast/irregular heartbeat, severe dizziness, fainting.