Medically reviewed on March 7, 2017
What is fluoxetine?
Fluoxetine is a selective serotonin reuptake inhibitors (SSRI) antidepressant. Fluoxetine affects chemicals in the brain that may be unbalanced in people with depression, panic, anxiety, or obsessive-compulsive symptoms.
Fluoxetine is sometimes used together with another medication called olanzapine (Zyprexa) to treat manic depression caused by bipolar disorder. This combination is also used to treat depression after at least 2 other medications have been tried without successful treatment of symptoms.
If you also take olanzapine (Zyprexa), read the Zyprexa medication guide and all patient warnings and instructions provided with that medication.
Fluoxetine may also be used for purposes not listed in this medication guide.
You must wait at least 14 days after stopping an MAO inhibitor before you can take fluoxetine. You must wait 5 weeks after stopping fluoxetine before you can take thioridazine or an MAOI.
Some young people have thoughts about suicide when first taking an antidepressant. Stay alert to changes in your mood or symptoms. Report any new or worsening symptoms to your doctor.
Before taking this medicine
Do not use fluoxetine if you have taken an MAO inhibitor in the past 14 days. A dangerous drug interaction could occur. MAO inhibitors include isocarboxazid, linezolid, phenelzine, rasagiline, selegiline, and tranylcypromine. You must wait at least 14 days after stopping an MAO inhibitor before you can take fluoxetine. You must wait 5 weeks after stopping fluoxetine before you can take thioridazine or an MAOI.
You should not use fluoxetine if you are allergic to it, if you also take pimozide or thioridazine, or if you are being treated with methylene blue injection.
Some medicines can interact with fluoxetine and cause a serious condition called serotonin syndrome. Be sure your doctor knows about all other medicines you use. Ask your doctor before making any changes in how or when you take your medications.
To make sure fluoxetine is safe for you, tell your doctor if you have:
cirrhosis of the liver;
bipolar disorder (manic depression);
a history of drug abuse or suicidal thoughts; or
if you are being treated with electroconvulsive therapy (ECT).
Some young people have thoughts about suicide when first taking an antidepressant. Your doctor should check your progress at regular visits. Your family or other caregivers should also be alert to changes in your mood or symptoms.
Taking an SSRI antidepressant during pregnancy may cause serious lung problems or other complications in the baby. However, you may have a relapse of depression if you stop taking your antidepressant. Tell your doctor right away if you become pregnant. Do not start or stop taking this medicine during pregnancy without your doctor's advice.
Fluoxetine can pass into breast milk and may harm a nursing baby. Tell your doctor if you are breast-feeding a baby.
Fluoxetine is not approved for use by anyone younger than 18 years old.
How should I take fluoxetine?
Follow all directions on your prescription label. Your doctor may occasionally change your dose. Do not take this medicine in larger or smaller amounts or for longer than recommended.
Do not crush, chew, break, or open a delayed-release capsule. Swallow it whole.
Measure liquid medicine with the dosing syringe provided, or with a special dose-measuring spoon or medicine cup. If you do not have a dose-measuring device, ask your pharmacist for one.
To treat premenstrual dysphoric disorder, the usual dose of fluoxetine is once daily while you are having your period, or 14 days before you expect your period to start. Follow your doctor's instructions.
It may take up to 4 weeks before your symptoms improve. Keep using the medication as directed and tell your doctor if your symptoms do not improve.
Do not stop using fluoxetine suddenly, or you could have unpleasant withdrawal symptoms. Ask your doctor how to safely stop using fluoxetine.
Store at room temperature away from moisture and heat.
What happens if I miss a dose?
Take the missed dose as soon as you remember. Skip the missed dose if it is almost time for your next scheduled dose. Do not take extra medicine to make up the missed dose.
If you miss a dose of Prozac Weekly, take the missed dose as soon as you remember and take the next dose 7 days later. However, if it is almost time for the next regularly scheduled weekly dose, skip the missed dose and take the next one as directed. Do not take extra medicine to make up the missed dose.
What happens if I overdose?
Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.
What should I avoid while taking fluoxetine?
Drinking alcohol can increase certain side effects of fluoxetine.
Ask your doctor before taking a nonsteroidal anti-inflammatory drug (NSAID) for pain, arthritis, fever, or swelling. This includes aspirin, ibuprofen (Advil, Motrin), naproxen (Aleve), celecoxib (Celebrex), diclofenac, indomethacin, meloxicam, and others. Using an NSAID with fluoxetine may cause you to bruise or bleed easily.
This medication may impair your thinking or reactions. Be careful if you drive or do anything that requires you to be alert.
Fluoxetine side effects
Report any new or worsening symptoms to your doctor, such as: mood or behavior changes, anxiety, panic attacks, trouble sleeping, or if you feel impulsive, irritable, agitated, hostile, aggressive, restless, hyperactive (mentally or physically), more depressed, or have thoughts about suicide or hurting yourself.
Call your doctor at once if you have:
blurred vision, tunnel vision, eye pain or swelling, or seeing halos around lights;
low levels of sodium in the body--headache, confusion, slurred speech, severe weakness, vomiting, loss of coordination, feeling unsteady;
severe nervous system reaction--very stiff (rigid) muscles, high fever, sweating, confusion, fast or uneven heartbeats, tremors, feeling like you might pass out; or
severe skin reaction--fever, sore throat, swelling in your face or tongue, burning in your eyes, skin pain, followed by a red or purple skin rash that spreads (especially in the face or upper body) and causes blistering and peeling.
Common side effects may include:
sleep problems (insomnia), strange dreams;
headache, dizziness, vision changes;
tremors or shaking, feeling anxious or nervous;
pain, weakness, yawning, tired feeling;
upset stomach, loss of appetite, nausea, vomiting, diarrhea;
dry mouth, sweating, hot flashes;
changes in weight or appetite;
stuffy nose, sinus pain, sore throat, flu symptoms; or
decreased sex drive, impotence, or difficulty having an orgasm.
This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.
See also: Side effects (in more detail)
What other drugs will affect fluoxetine?
Taking fluoxetine with other drugs that make you sleepy or slow your breathing can cause dangerous side effects or death. Ask your doctor before taking a sleeping pill, narcotic pain medicine, prescription cough medicine, a muscle relaxer, or medicine for anxiety, depression, or seizures.
Many drugs can interact with fluoxetine. Not all possible interactions are listed here. Tell your doctor about all your current medicines and any you start or stop using, especially:
any other antidepressant;
tryptophan (sometimes called L-tryptophan);
This list is not complete and many other drugs can interact with fluoxetine. This includes prescription and over-the-counter medicines, vitamins, and herbal products. Give a list of all your medicines to any healthcare provider who treats you.
Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.
Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.
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