Fluoxetine (Prozac): Uses, Side Effects & Safety

Fluoxetine is the generic name for Prozac. It is a prescription antidepressant called a selective serotonin reuptake inhibitor, or SSRI ^6,8.

This guide explains the uses, side effects, and safety information for fluoxetine (Prozac) in plain language. It covers approved uses, common side effects, major warnings, drug interactions, and safe use.

The full benefits of fluoxetine may take several weeks to appear ^6,9. Close monitoring is important when treatment starts or the dose changes ^2,5.

This guide does not replace medical advice. Ask your prescriber or pharmacist about your health, medicines, and treatment plan.

Fluoxetine is an antidepressant in the SSRI drug class ^6,8. Prozac is a brand name for fluoxetine ^8,9.

SSRIs change chemical signaling between nerve cells in the brain. Fluoxetine is available only with a prescription.

Approved uses and age limits depend on the condition being treated ^2,5,8. Follow the label and directions that come with your prescription.

Fluoxetine blocks the transporter that moves serotonin back into presynaptic nerve cells. “Presynaptic” refers to the nerve cell that releases a chemical signal.

This action increases serotonin activity in the brain. Serotonin is a natural chemical that helps control mood ^6,9.

Treatment response can differ from person to person. Discuss your progress and concerns at follow-up visits.

Fluoxetine comes as a tablet, capsule, delayed-release capsule, and liquid ^6,8. Standard forms may be taken each day ⁶.

A delayed-release capsule may be prescribed once a week ⁶. Follow the schedule on your prescription label.

Fluoxetine may be taken with or without food ^6,9. Take it exactly as directed ^3,6.

The full benefit may take four to five weeks or longer ⁶. Keep taking the medicine as prescribed while waiting for its effects ^6,9.

Contact the prescriber if symptoms become worse or do not improve ^6,9. Do not change the dose on your own ^3,6.

Approved uses vary by fluoxetine product and age. Fluoxetine products may be used for these conditions:

Approval for children differs by condition. Safety and effectiveness are not established for depression in children younger than eight.

Safety and effectiveness are not established for OCD in children younger than seven. Some fluoxetine products are not approved in children for bulimia or panic disorder ^2,5.

A clinician should confirm whether fluoxetine is right for a child. The clinician should also check the product and approved use.

Children and teens should have their height and weight checked during treatment ^2,5. Families should watch for changes in mood or behavior ^3,5.

Fluoxetine may be combined with olanzapine for depression linked to bipolar I disorder ^4,5. This combination may also treat depression that did not improve after at least two other treatments ^5,8.

Fluoxetine alone is not indicated for these two uses ⁴. These uses require treatment with fluoxetine and olanzapine together.

Antidepressant treatment may trigger manic symptoms in some people ^1,2. Mania may cause major changes in mood, energy, sleep, or behavior ^2,5.

“Off-label” means the FDA-approved label does not cover that specific use. A prescription is still required.

Fluoxetine is sometimes used for post-traumatic stress disorder or attention-deficit disorder ⁶. Other off-label uses include sleep problems, headaches, Tourette syndrome, obesity, and phobias ⁶.

It has also been used for alcohol-related problems and some sexual problems ⁶. These uses are separate from the approved uses listed above.

Ask why off-label treatment is being suggested. Discuss its possible benefits, risks, limits, and other choices with the prescriber.

Do not share fluoxetine with anyone else. This medicine is only for the person named on the prescription ⁹.

Prozac side effects vary between people. Common effects may include the following:

Water, sugar-free gum, or sugar-free hard candy may ease dry mouth ⁹. Ask a clinician before taking another product for side effects.

Fluoxetine may feel stimulating and may cause anxiety, agitation, or poor sleep. A clinician may suggest morning dosing when it causes insomnia.

Do not change the time or dose without guidance ^1,3. Your prescriber can advise you based on your prescription.

Fluoxetine may also affect judgment, movement, or thinking ^3,5. Avoid driving until you know how it affects you ^3,9.

Sexual Prozac side effects can affect daily life and relationships. Reported problems include:

It may feel hard to discuss these effects. A prescriber can review the symptom and possible treatment choices.

Fluoxetine may also change appetite or weight ^1,2. Weight may rise or fall during treatment.

Loss of appetite was also reported in Prozac clinical trials. Discuss lasting or troubling changes with the care team.

Children and teens need height and weight checks during treatment ^2,5. Families should report concerns about appetite, weight, or growth.

Many side effects begin early and may ease with time. Some depend on the dose and length of treatment.

Contact the prescriber if an effect lasts or causes distress. A clinician may consider changing the dose or medicine.

Do not change your prescribed dosing regimen without medical guidance; if a missed dose is almost due to be followed by the next dose, skip the missed dose ^3,6. Sudden changes may cause withdrawal symptoms or make the condition worse ^2,9.

Keep all planned follow-up visits ^2,5. Contact the care team between visits if symptoms cause concern ^2,5.

A short symptom record may help with the discussion. Include when each symptom began and when it occurs.

Fluoxetine carries a boxed warning about suicidal thoughts and actions ^4,5,6. This increased risk affects some children, teens, and young adults ^4,5,6.

The risk needs close attention during the first few months ^5,6. Watch for new or sudden mood or behavior changes after a dose change ^5,6.

Families and caregivers should watch for sudden changes in mood or behavior ^2,5. They should also watch for changes in thoughts, actions, and feelings ^2,5.

Warning signs may include worse depression, panic, aggression, or severe restlessness ^2,5. Other signs include agitation, unsafe impulses, or unusual behavior ^2,5.

If suicidal thoughts or actions occur, call emergency services or seek emergency care now ^2,5. Stay with a person at immediate risk while help is arranged.

Mania is another serious concern. Possible signs include:

If signs of mania appear, contact the prescriber right away ². Do not change the fluoxetine dose on your own ³.

Serotonin syndrome is a life-threatening reaction linked to excess serotonin activity ⁴. Fluoxetine can cause it when used alone ⁴.

The risk rises when fluoxetine is combined with other drugs that affect serotonin ⁴. Symptoms may include:

If these symptoms suggest serotonin syndrome, seek immediate medical care ³. Do not wait for the symptoms to pass.

Fluoxetine medication guides list seizures or convulsions among serious possible side effects. If you have a seizure, call your healthcare provider right away or call 911 if it is an emergency.

A severe allergy may cause trouble breathing or swelling of the face or mouth ^2,5. It may also cause hives, blisters, or tongue swelling ^2,5.

If trouble breathing or facial swelling occurs, call emergency services now ^2,5. A new rash or hives should be reported to the prescriber ³.

Fluoxetine may cause serious allergic reactions or rashes ⁴. Report new rashes so the cause can be assessed.

Fluoxetine may raise the risk of bruising or bleeding ^2,3. The risk is greater with drugs that affect blood clotting ^2,3.

Report unusual bleeding or increased bruising to the prescriber ³. Do not stop prescribed blood thinners on your own.

Fluoxetine may cause low blood sodium, called hyponatremia ³. Possible signs include:

Older adults have a higher risk of low sodium with fluoxetine ^2,8. Severe cases have involved fainting, seizures, coma, breathing failure, and death ³.

Fluoxetine may cause an eye problem in people who are at risk ⁵. Eye pain, vision changes, redness, or eye swelling need medical review ⁵.

Fluoxetine has also been linked to QT prolongation ^5,7. This is a change in the heart’s electrical activity.

QT prolongation can lead to dangerous heart rhythms ^5,7. Signs may include an uneven heartbeat, shortness of breath, dizziness, or fainting ^5,7.

If fainting or severe shortness of breath occurs, seek emergency care now ^5,7. For a fast, slow, or irregular heartbeat, call your healthcare provider right away or call emergency services if it is an emergency ^5,7.

Fluoxetine must not be used close in time to an MAOI ^2,4. An MAOI is a type of antidepressant.

Combining these medicines may cause a life-threatening reaction ^2,4. Linezolid and intravenous methylene blue can also act as MAOIs ⁴.

Wait at least 14 days after stopping an MAOI before starting fluoxetine ^2,4. A doctor may give different directions in a special case.

Wait at least five weeks after stopping fluoxetine before starting an MAOI ^2,4. This long gap is needed because fluoxetine stays in the body.

Other drugs and supplements may increase the risk of serotonin syndrome. Examples include:

Warfarin, aspirin, ibuprofen, and naproxen may increase bleeding risk ^2,3. Warfarin use may need closer PT/INR blood tests.

Pimozide and thioridazine must not be used with fluoxetine ^2,4. These combinations can cause serious heart rhythm problems ^2,4.

Do not start thioridazine (Mellaril) within five weeks after stopping fluoxetine ². Ask a pharmacist to check your full medicine list.

Give the care team a list of all drugs and supplements you use ^3,9. Include prescription drugs, store-bought products, vitamins, and herbs ^3,9.

Ask before starting or stopping another product ⁶. This includes pain relievers and herbal supplements.

Tell the prescriber about certain health concerns before taking fluoxetine. These include:

Tell the prescriber about a personal or family history of a long QT interval ⁶. This heart problem may cause an uneven heartbeat, fainting, or sudden death ⁶.

Older adults need added care because low sodium is more likely. Tell the care team about past suicidal thoughts, plans, or attempts ⁹.

Pregnancy needs a personal review of benefits and risks. Fluoxetine use during pregnancy has been linked to fetal and newborn concerns.

Treatment may still be needed during pregnancy in some cases. Discuss pregnancy or plans for pregnancy with the prescriber.

Also tell the prescriber if you are breastfeeding ⁹. One clinical source advises another drug or stopping breastfeeding due to reported infant harm.

If you miss a daily dose, skip it and return to your normal schedule ⁹. Do not take two doses at once ⁹.

Weekly delayed-release fluoxetine may need different advice. Follow its label or contact the pharmacist.

Do not stop fluoxetine without talking to the prescriber ^2,3. Stopping too fast may cause:

Take fluoxetine exactly as prescribed ^3,6. Keep follow-up visits with the care team ^2,9.

Avoid driving until you know how fluoxetine affects your judgment and movement ^3,9. Ask for help if side effects make daily tasks unsafe.

Fluoxetine may treat depression, OCD, bulimia, panic disorder, and PMDD ^2,6,8. The exact approved uses depend on the product and age ^2,5,8.

Fluoxetine with olanzapine may treat bipolar I depression ^4,5. The combination may also treat depression that did not improve with prior care ^4,5.

Safe treatment requires checks for side effects, mood changes, and drug interactions. Take the medicine as prescribed and keep all follow-up visits ^2,9.

If suicidal behavior occurs, call emergency services or seek emergency care now ^2,5. Seek immediate care for suspected serotonin syndrome ³.

Call emergency services for a seizure, severe breathing trouble, or facial swelling ^2,3,5. Seek emergency care for fainting or a serious irregular heartbeat ^5,7.

For lasting common side effects, contact the prescriber. Do not change the dose or stop treatment on your own ^1,3.