Generic name: fluoxetine [ floo-OX-e-teen ]
Brand names: Prozac, Sarafem, Rapiflux, Selfemra
Drug class: Selective serotonin reuptake inhibitors

Medically reviewed by Kaci Durbin, MD. Last updated on Nov 28, 2024.

What is fluoxetine?

Fluoxetine is a selective serotonin reuptake inhibitor (SSRI) antidepressant. Fluoxetine inhibits the uptake of serotonin by a nerve cells (neurons) and helps people with depression, panic, anxiety, or obsessive-compulsive symptoms.

Fluoxetine is a prescription medicine used to treat major depressive disorder, bulimia nervosa (an eating disorder), obsessive-compulsive disorder, panic disorder, and premenstrual dysphoric disorder (PMDD).

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.

Warnings

You should not use fluoxetine if you also take pimozide or thioridazine, or if you are being treated with methylene blue injection.

Do not use fluoxetine if you have used an MAO inhibitor in the past 14 days (such as isocarboxazid, rasagiline, selegiline, phenelzine, or transcypromine). Do not use fluoxetine with thioridazine, linezolid, pimozide, or methylene blue injection.

You must wait at least 14 days after stopping an MAO inhibitor before you 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.

Fluoxetine could impair judgment, thinking, or motor skills. Use caution when operating machinery.

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.

Do not stop using fluoxetine without first asking your doctor.

Before taking this medicine

You should not use this medicine if you are allergic to fluoxetine, if you also take pimozide or thioridazine.

Do not use fluoxetine if you have used an MAO inhibitor in the past 14 days. A dangerous drug interaction could occur. MAO inhibitors include isocarboxazid, linezolid, methylene blue injection, phenelzine, rasagiline, selegiline, and tranylcypromine. You must wait at least 14 days after stopping an MAO inhibitor before you take fluoxetine. You must wait 5 weeks after stopping fluoxetine before you can take thioridazine or an MAOI.

Tell your doctor about all other antidepressants you take, especially Celexa, Cymbalta, Desyrel, Effexor, Lexapro, Luvox, Oleptro, Paxil, Pexeva, Symbyax, Viibryd, or Zoloft.

To make sure fluoxetine is safe for you, tell your doctor if you have ever had:

• cirrhosis of the liver;

• urination problems;

• diabetes;

• narrow-angle glaucoma;

• seizures or epilepsy;

• sexual problems;

• bipolar disorder (manic depression);

• drug abuse or suicidal thoughts; or

• 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.

Older adults may be more sensitive to the effects of fluoxetine.

Ask your doctor about taking fluoxetine if you are pregnant. Taking an SSRI antidepressant during late pregnancy may cause serious medical 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. If you are pregnant, your name may be listed on a pregnancy registry to track the effects of fluoxetine on the baby.

If you are breastfeeding, tell your doctor if you notice agitation, fussiness, feeding problems, or poor weight gain in the nursing baby.

How should I take fluoxetine?

Take fluoxetine exactly as prescribed by your doctor. Follow all directions on your prescription label and read all medication guides or instruction sheets. Your doctor may occasionally change your dose.

Swallow the delayed-release capsule whole and do not crush, chew, break, or open it.

Measure liquid medicine carefully. Use the dosing syringe provided, or use a medicine dose-measuring device (not a kitchen spoon).

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.

Tell your doctor if you have any changes in sexual function, such as loss of interest in sex, trouble having an orgasm, or (in men) problems with erections or ejaculation. Some sexual problems can be treated.

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.

Dosing information

Usual Adult Dose for Bulimia:

Immediate-release oral formulations: 60 mg orally once a day in the morning

Comments:
-Some patients may need to be started at a lower dose and titrated up over several days to the recommended dose.
-Daily doses greater than 60 mg have not been systematically studied for the treatment of bulimia.

Use: Acute and maintenance treatment of binge-eating and vomiting behaviors in moderate to severe bulimia nervosa

Usual Adult Dose for Depression:

Immediate-release oral formulations:
Initial dose: 20 mg orally once a day in the morning, increased after several weeks if sufficient clinical improvement is not observed
Maintenance dose: 20 to 60 mg orally per day
Maximum dose: 80 mg orally per day

Delayed release oral capsules:
Initial dose: 90 mg orally once a week, commenced 7 days after the last daily dose of immediate-release fluoxetine 20 mg formulations.

Comments:
-Doses above 20 mg per day may be given in divided doses, in the morning and at noon.
-The full effect may be delayed until after at least 4 weeks of treatment.
-If a satisfactory response with the once weekly oral fluoxetine is not maintained, a change back to daily fluoxetine dosing using the immediate-release oral formulations should be considered.
-Acute episodes of Major Depressive Disorder (MDD) require several months or longer of sustained pharmacologic therapy.
-Whether the dose needed to induce remission is the same as the dose needed to maintain and/or sustain euthymia is unknown.

Use: Acute and maintenance treatment of MDD

Usual Adult Dose for Obsessive Compulsive Disorder:

Immediate-release oral formulations:
-Initial dose: 20 mg orally once a day in the morning, increased after several weeks if sufficient clinical improvement is not observed.
-Maintenance dose: 20 to 60 mg orally per day
-Maximum dose: 80 mg orally per day

Comments:
-Doses above 20 mg per day may be given in divided doses, in the morning and at noon.
-The full effect may be delayed until after at least 5 weeks of treatment.

Use: Acute and maintenance treatment of obsessions and compulsions in patients with Obsessive Compulsive Disorder (OCD)

Usual Adult Dose for Panic Disorder:

Immediate-release oral formulations:
-Initial dose: 10 mg orally once a day, increased after one week to 20 mg orally once a day
-Maintenance dose: 20 to 60 mg orally per day
-Maximum dose: 60 mg orally per day

Comments:
-Doses above 20 mg per day may be given in divided doses, in the morning and at noon.
-A dose increase may be considered after several weeks if clinical improvement is not observed.
-Doses greater than 60 mg per day have not been systematically studied for the treatment of panic disorder.

Use: Acute treatment of panic disorder with/without agoraphobia

Usual Adult Dose for Premenstrual Dysphoric Disorder:

Immediate-release oral formulations:
Initial dose:
-Continuous regimen: 20 mg orally once a day on every day of the menstrual cycle
-Cyclic regimen: 20 mg orally once a day starting 14 days prior to the anticipated start of menstruation through to the first full day of menses, and repeated with each new cycle
Maintenance dose: 20 to 60 mg per day for either the continuous or intermittent regimens
Maximum dose: 80 mg orally per day

Comments:
-A daily dose of 60 mg has not been shown to be significantly more effective than 20 mg daily.
-Daily doses above 60 mg have not been systematically studied in patients with this condition.
-The 20 mg daily dosage has been shown to be effective for up to 6 months of treatment.

Use: Treatment of premenstrual dysphoric disorder (PMDD)

Usual Pediatric Dose for Depression:

Immediate-release oral formulations:
8 to 18 years:
Initial dose: 10 to 20 mg orally once a day; the 10 mg daily dose may be increased after one week to 20 mg orally once a day

Lower weight children:
-Initial dose: 10 mg orally once a day, increased to 20 mg orally once a day after several weeks if sufficient clinical improvement is not observed
-Maintenance dose: 10 to 20 mg orally once a day

Comments:
-The full effect may be delayed until after at least 4 weeks of treatment.
-The potential risks versus clinical need should be assessed prior to using this drug in children and adolescents.

Use: Acute and maintenance treatment of MDD

Usual Pediatric Dose for Obsessive Compulsive Disorder:

Immediate-release oral formulations:
7 to 17 years:
Adolescents and higher weight children:
-Initial dose: 10 mg orally once a day, increased to 20 mg orally once a day after 2 weeks
-Maintenance dose: 20 to 60 mg orally per day
-Maximum dose: 60 mg orally per day

Lower weight children:
-Initial dose: 10 mg orally once a day, increased after several weeks if sufficient clinical improvement is not observed
-Maintenance dose: 20 to 30 mg orally once a day
-Maximum dose: 60 mg orally per day

Comments:
-Additional dose increases may be considered after several more weeks if clinical improvement is insufficient.
-Doses above 20 mg per day may be given in divided doses, in the morning and at noon.
-In lower weight children, there is minimal experience with doses greater than 20 mg per day, and none with doses greater than 60 mg per day.
-The full effect may be delayed until after at least 5 weeks of treatment.
-The potential risks versus clinical need should be assessed prior to using this drug in children and adolescents.

Use: Acute and maintenance treatment of obsessions and compulsions in patients with
OCD

What happens if I miss a dose?

Take the medicine as soon as you can, but skip the missed dose if it is almost time for your next dose. Do not take two doses at one time.

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 to avoid

Drinking alcohol can increase certain side effects of fluoxetine.

Avoid driving or hazardous activity until you know how fluoxetine will affect you. Your reactions could be impaired.

Fluoxetine side effects

Get emergency medical help if you have signs of an allergic reaction to fluoxetine (hives, difficult breathing, swelling in your face or throat) or a severe skin reaction (fever, sore throat, burning eyes, skin pain, red or purple skin rash with blistering and peeling).

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.

Fluoxetine may cause serious side effects. Call your doctor at once if you have:

• blurred vision, tunnel vision, eye pain or swelling, or seeing halos around lights;

• fast or pounding heartbeats, fluttering in your chest, shortness of breath, and sudden dizziness (like you might pass out);

• low levels of sodium in the body - headache, confusion, slurred speech, severe weakness, vomiting, loss of coordination, feeling unsteady; or

• severe nervous system reaction - very stiff (rigid) muscles, high fever, sweating, confusion, fast or uneven heartbeats, tremors, feeling like you might pass out.

Seek medical attention right away if you have symptoms of serotonin syndrome, such as: agitation, hallucinations, fever, sweating, shivering, fast heart rate, muscle stiffness, twitching, loss of coordination, nausea, vomiting, or diarrhea.

Common fluoxetine side effects may include:

• sleep problems (insomnia), strange dreams;
• headache, dizziness, drowsiness, 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.

Related/similar drugs

What other drugs will affect fluoxetine?

Fluoxetine can cause a serious heart problem. Your risk may be higher if you also use certain other medicines for infections, asthma, heart problems, high blood pressure, depression, mental illness, cancer, malaria, or HIV.

Using fluoxetine with other drugs that make you drowsy can worsen this effect. Ask your doctor before using opioid medication, a sleeping pill, a muscle relaxer, or medicine for anxiety or seizures.

Ask your doctor before taking a nonsteroidal anti-inflammatory drug (NSAID) such as 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.

Tell your doctor about all your current medicines. Many drugs can affect fluoxetine, especially:

• any other antidepressant;

• St. John's Wort;

• tryptophan (sometimes called L-tryptophan);

• a blood thinner - warfarin, Coumadin, Jantoven;

• medicine to treat anxiety, mood disorders, thought disorders, or mental illness - amitriptyline, buspirone, desipramine, lithium, nortriptyline, and many others;

• medicine to treat ADHD or narcolepsy - Adderall, Concerta, Ritalin, Vyvanse, Zenzedi, and others;

• migraine headache medicine - rizatriptan, sumatriptan, zolmitriptan, and others; or

• narcotic pain medicine - fentanyl, tramadol.

This list is not complete and many other drugs may affect fluoxetine. This includes prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible drug interactions are listed here.

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Further information

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use fluoxetine 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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