Prozac, Fluoxetine DR

Introduction

Written by Sarah Lewis, PharmD
Medically reviewed by Victor Nguyen, PharmD, MBA
Updated on July 19, 2023

Fluoxetine (floo OKS e teen) is a generic medication prescribed for depression and certain other mental health conditions. Fluoxetine belongs to a group of drugs called selective serotonin reuptake inhibitor (SSRI) antidepressants.

The Food and Drug Administration (FDA) has approved fluoxetine for:

• depression
• treatment-resistant depression (depression that doesn’t respond to standard treatment), along with olanzapine
• obsessive-compulsive disorder (OCD)
• bulimia nervosa
• panic disorder
• premenstrual dysphoric disorder (a very severe form of premenstrual syndrome [PMS])
• bipolar disorder, along with olanzapine

These approved uses differ based on the form of fluoxetine your doctor prescribes.

This article doesn’t provide coupons for all forms of fluoxetine. To find coupons for fluoxetine delayed-release oral capsule, see this article.

Boxed warning: Risk of suicidal thoughts and behaviors

Fluoxetine has a boxed warning about the risk of suicidal thoughts and behaviors. Boxed warnings are the most serious warnings from the FDA.

For details, see the “Interactions and warnings for fluoxetine” section.

Side effects of fluoxetine

Fluoxetine may cause mild or serious side effects. More common mild side effects of fluoxetine and its serious side effects are listed below. This article doesn’t include all possible side effects of the drug. Side effects can vary based on your age, overall health, and any other medications you take.

To learn more about fluoxetine’s side effects, ask your doctor or pharmacist. You can also refer to the prescribing information for fluoxetine listed in the “Article resources” section.

Mild side effects

More common mild side effects reported with some forms of fluoxetine are listed below. These side effects may differ based on the form of fluoxetine you take.

This article doesn’t include all possible mild side effects of the drug. To learn more about fluoxetine’s side effects based on the form, refer to the prescribing information for fluoxetine listed in the “Article resources” section.

With many drugs, mild side effects may go away within a few days or a couple of weeks. If the side effects are bothersome, tell your doctor or pharmacist. They may be able to suggest ways to manage them.

Fluoxetine oral capsule’s mild side effects include:

• diarrhea
• nausea
• sleep problems
• sleepiness
• mild allergic reaction*

Fluoxetine oral tablet’s mild side effects include:

• dizziness
• headache
• fatigue (low energy)
• nausea
• mild allergic reaction*

* For details about this side effect, see the “Interactions and warnings for fluoxetine” section.

Serious side effects

Serious side effects of fluoxetine are listed below. These side effects may differ based on the form of fluoxetine you take.

This article doesn’t include all possible serious side effects of the drug. To learn more about fluoxetine’s side effects based on the form, refer to the prescribing information for fluoxetine listed in the “Article resources” section.

With many drugs, serious side effects are possible but not common. If you have serious side effects from this drug, call your doctor right away. If you’re having severe symptoms or a medical emergency, call 911 or a local emergency number.

In general, fluoxetine’s serious side effects include:

• closed angle glaucoma (sudden buildup of pressure inside the eye, also called angle-closure glaucoma)
• anxiety, nervousness, or sleep problems, which can be severe enough to stop fluoxetine treatment*
• changes in mental and physical abilities, which can affect the safety of performing hazardous tasks such as driving
• heart rhythm problems
• increased risk of bleeding and bruising
• low sodium (salt) levels
• seizures
• serotonin syndrome (too much of the chemical serotonin in the body), which can be life threatening
• sexual problems
• weight loss†
• boxed warning: risk of suicidal thoughts and behaviors‡
• severe allergic reaction‡

* It’s important to not stop taking fluoxetine without first talking with your doctor.
† Significant weight loss may be unwanted during treatment for bulimia nervosa or depression. Be sure to talk with your doctor if you experience significant weight loss with fluoxetine treatment.
‡ For details about this side effect, see the “Interactions and warnings for fluoxetine” section.

Uses of fluoxetine

The Food and Drug Administration (FDA) approves prescription drugs such as fluoxetine for certain conditions. Approved uses for fluoxetine are described below. These uses differ based on the form of fluoxetine prescribed.

Use for certain mental health conditions

Doctors may prescribe fluoxetine oral capsule, delayed-release* oral capsule, and oral liquid solution to treat depression. They may also prescribe the oral capsule or liquid solution to treat certain other mental health conditions, including:

• obsessive-compulsive disorder (OCD)
• the eating disorder bulimia nervosa
• panic disorder

Fluoxetine oral capsule is prescribed together with olanzapine to treat the following mental health conditions:

• bipolar disorder
• treatment-resistant depression (depression that doesn’t respond to standard treatment)

Fluoxetine is used for depression in adults and children 8 years and older. For other mental health conditions, fluoxetine is used in adults and children 7 years and older. Fluoxetine is usually prescribed as a long-term treatment.

With depression and other mental health conditions, you have changes in the way you think, feel, or act. The symptoms you have can vary with the specific mental health condition. But for all these conditions, the symptoms interfere with daily life. Fluoxetine can help lower your symptoms.

Doctors may not prescribe fluoxetine in certain situations, such as if you take certain other medications.

* “Delayed release” means the drug is released into your body after it passes through your stomach.

Use for premenstrual dysphoric disorder

Doctors may prescribe fluoxetine oral tablet for treating premenstrual dysphoric disorder (PMDD). It’s used for this purpose in adults. It’s usually prescribed as a long-term treatment.

With PMDD, you might have symptoms that begin about a week before your menstrual period. Symptoms can also last for the first few days of your period. This condition is like a severe form of premenstrual syndrome (PMS). It can include physical symptoms, such as breast tenderness. It can also involve mental or behavioral symptoms, such as extreme mood changes, sadness, or hopelessness.

Doctors may not prescribe fluoxetine tablet in certain situations, such as if you take certain other medications.

Common questions about fluoxetine

Below you’ll find answers to a few commonly asked questions about fluoxetine.

How do side effects of fluoxetine in females compare with those seen in males?

In general, the side effects of fluoxetine are similar regardless of biological sex. But fluoxetine can cause sexual side effects, including:

• decreased sex drive
• delayed orgasm or ejaculation
• inability to have an orgasm or ejaculation
• problems getting or keeping an erection

Keep in mind that the conditions that fluoxetine treats, such as depression, can also cause sexual problems.

It’s important to tell your doctor about any sexual problems you have. They can determine the most likely cause and recommend ways to help.

Note: In this article, we use the terms “male” and “female” to refer to someone’s sex assigned at birth. For information about the difference between sex and gender, see this article.

How does fluoxetine work? And how long does it take to start working?

The exact way fluoxetine works isn’t known. It likely works by affecting levels of brain chemicals called neurotransmitters. The main neurotransmitter that fluoxetine affects is serotonin, which plays a role in mood.

Fluoxetine can start reducing some symptoms of mental health conditions within a couple of weeks. But it can take several weeks to see the full effect of fluoxetine. In general, this means it can take 4 weeks or longer for fluoxetine to fully work.

If you’d like to know more about what to expect with fluoxetine treatment, talk with your doctor or pharmacist.

Interactions and warnings for fluoxetine

Below, you’ll find information about fluoxetine’s possible interactions and warnings.

Interactions of fluoxetine

Certain things may affect how a drug works. These include getting vaccines, consuming alcohol or certain foods, or taking the drug with other medications. This effect is called a drug interaction.

Before you take fluoxetine, ask your doctor to check for possible interactions. Be sure to tell them about any of the following you take or use:

• prescription or over-the-counter drugs
• vitamins, herbs, or supplements

To learn about drug-condition interactions, see the “Warnings for fluoxetine” section below.

Warnings for fluoxetine

Some people should not take fluoxetine, and others should take it cautiously.

Boxed warning: Risk of suicidal thoughts and behaviors

Fluoxetine has a boxed warning about the risk of suicidal thoughts and behaviors. Boxed warnings are the most serious warnings from the Food and Drug Administration (FDA).

With antidepressants such as fluoxetine, there’s an increased risk of suicidal thoughts and actions in children and in adults younger than 25 years. This risk is highest during the first few months of treatment and with dosage changes.

Due to this risk, you and your doctor should monitor for new or worsening suicidal thoughts and behaviors while you’re taking fluoxetine. Your doctor might also recommend that you ask others to watch for symptoms, such as family members or a caregiver. Symptoms may include changes in thoughts, feelings, behaviors, or mood.

If you have thoughts about harming yourself, tell your doctor or call 911 (or your local emergency number). You can also call the 988 Suicide and Crisis Lifeline at 988 or text HOME to the Crisis Textline at 741741.

To learn more about this boxed warning, talk with your doctor or pharmacist.

Other warnings

Fluoxetine could cause harm to people with certain health conditions. This effect is called a drug-condition interaction. Other factors can also affect whether fluoxetine is a safe option for you. These warnings may differ based on the form of fluoxetine you take.

Ask your doctor about specific warnings for fluoxetine, and be sure to tell your doctor about your:

• current health, including any allergies to medications
• past health conditions or surgeries

Allergic reaction

Fluoxetine can cause an allergic reaction in some people. Severe allergic reactions are rare but possible.

If you’ve had an allergic reaction to fluoxetine or any of its ingredients, your doctor will likely not prescribe fluoxetine. They can tell you about medications that are safer options for you.

A mild allergic reaction may cause the following symptoms:

• skin rash
• itchiness
• flushing (temporary warmth, redness, or deepening of skin color)

A severe allergic reaction may cause the following symptoms:

• swelling under your skin, usually in your hands, feet, eyelids, or lips
• swelling of your mouth, throat, or tongue, which can cause breathing problems

If you have an allergic reaction to fluoxetine, call your doctor right away. If you have severe symptoms, call 911 or a local emergency number.

Overdose of fluoxetine

You should not take more fluoxetine than your doctor prescribes. For some drugs, doing so may lead to harmful effects or overdose.

If you think you’ve taken too much fluoxetine, call your doctor or pharmacist right away. Or you could call 800-222-1222 to speak with someone at America’s Poison Centers. You can also use its online resource. If you have concerning symptoms, call 911 or a local emergency number immediately. You can also go to the closest emergency room.

Pregnancy or breastfeeding and fluoxetine

Information about fluoxetine and pregnancy and breastfeeding is described below.

Fluoxetine and pregnancy

There are risks to taking fluoxetine during pregnancy. But there are also risks with having untreated mental health conditions while pregnant. (Keep in mind that fluoxetine is used for treating certain mental health conditions.)

If you’re planning a pregnancy or can become pregnant, talk with your doctor about your treatment options during pregnancy. Together, you can discuss the risks and benefits of your treatment options and decide whether you should take fluoxetine during pregnancy.

If you do take fluoxetine while pregnant or become pregnant while taking an antidepressant, your doctor may suggest enrolling in a pregnancy registry. Pregnancy registries help gather information about how certain drugs affect pregnancy. You can register with the National Pregnancy Registry for Antidepressants by calling 844-405-6185 or visiting the registry website.

Fluoxetine and breastfeeding

Fluoxetine should not be taken while breastfeeding. If you’re currently breastfeeding or planning to do so, talk with your doctor before taking this medication. Your doctor may recommend other ways to feed your child during treatment with fluoxetine.

What to ask your doctor

Let your doctor know if you have questions about fluoxetine or would like more details about it.

Here’s a list of some possible questions you may want to ask your doctor:

• Am I at higher risk of side effects than other people?
• Do any of my other medications interact with fluoxetine?
• What’s the most important information I need to know about fluoxetine?

Resources

• Fluoxetine- fluoxetine capsule. (2023). https://nctr-crs.fda.gov/fdalabel/services/spl/set-ids/a1b40d46-5233-49d7-9833-762cb6999012/spl-doc
• Fluoxetine – fluoxetine solution. (2023). https://nctr-crs.fda.gov/fdalabel/services/spl/set-ids/3195db14-0cae-4b49-9fba-49b869fe92a8/spl-doc
• Fluoxetine- fluoxetine tablet. (2023). https://nctr-crs.fda.gov/fdalabel/services/spl/set-ids/dcebc7cf-6f95-4f7a-a22b-c7d2e0f04d74/spl-doc
• Fluoxetine hydrochloride- fluoxetine hydrochloride capsule, delayed release pellets. (2021). https://nctr-crs.fda.gov/fdalabel/services/spl/set-ids/887fc670-db67-4cfe-967b-46b38375dae5/spl-doc
• Food and Drug Administration. (2023). Orange Book: Approved drug products with therapeutic equivalence evaluations. https://www.accessdata.fda.gov/scripts/cder/ob/index.cfm

Disclaimer: Optum Perks has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.