Key takeaways

  • Fluoxetine is a generic prescription drug that’s used to treat certain mental health conditions in adults and children. These conditions include depression, obsessive-compulsive disorder, bulimia nervosa, and panic disorder.
  • Fluoxetine comes in four oral forms: capsules, delayed-release capsules, tablets, and a liquid solution. Fluoxetine capsules are also available as the brand-name drug Prozac.
  • Fluoxetine’s side effects include anxiety, difficulty sleeping, and sexual side effects. In serious cases, fluoxetine may increase the risk of suicidal thoughts and behaviors in certain people.

If you have certain mental health conditions, your doctor may prescribe fluoxetine for you.

It’s a prescription medication that’s used in certain situations to treat:

Depending on its prescribed use, fluoxetine can be used in adults and some children.

For more information about these conditions and how fluoxetine is used for them, see the “What is fluoxetine used for?” section.

Fluoxetine basics

Fluoxetine is a generic medication. It comes in multiple forms: capsules, delayed-release capsules, tablets, or a liquid solution that you swallow.

Fluoxetine capsules are also available as the brand-name drug Prozac. Fluoxetine tablets, delayed-release capsules, and liquid solution are only available as generic drugs.

Generic drugs are considered as safe and effective as the brand-name drug they’re based on, but they usually cost less.

If you have certain mental health conditions, your doctor may prescribe fluoxetine for you.

It’s a prescription medication that’s used in certain situations to treat:

  • Major depressive disorder (MDD): For this condition, the drug is given to adults and children ages 8 years and older. MDD is also called depression. With this condition, you have long-lasting feelings of sadness and a loss of interest. It consists of episodes of symptoms that last for at least 2 weeks, but the episodes often last longer.
  • Obsessive-compulsive disorder (OCD): For this condition, the drug is given to adults and children ages 7 years and older. With OCD, you have obsessions that lead to compulsive behaviors. For example, you may have obsessive worries about your house being unlocked, leading you to feel compelled to constantly check whether the door is locked.
  • Moderate or severe bulimia nervosa: For this condition, the drug is given to adults. Bulimia nervosa is sometimes just called bulimia. It’s an eating disorder that consists of episodes of binge eating followed by purging.
  • Panic disorder: For this condition, the drug is given to adults. With panic disorder, you have panic attacks, and you may have anxiety about having a panic attack.

It’s thought that depression and some other mental health conditions are caused by certain brain chemicals being out of balance. Examples of these chemicals include serotonin and dopamine. Fluoxetine works by helping to increase or balance levels of certain brain chemicals.

Fluoxetine may also be prescribed off-label to treat other mental health conditions, such as anxiety. With off-label use, a drug is prescribed for a condition it isn’t approved to treat. If you’re interested in learning more about off-label uses of fluoxetine, ask your doctor or pharmacist.

Like most drugs, fluoxetine may cause mild or serious side effects. The following lists describe some of the more common side effects that fluoxetine may cause. These lists don’t include all possible side effects.

Fluoxetine’s possible side effects are expected to be the same regardless of the form you’re prescribed. However, keep in mind that side effects of a drug can depend on:

  • your age
  • other health conditions you have
  • other medications you may be taking

Your doctor or pharmacist can tell you more about the potential side effects of fluoxetine. They can also suggest ways to help reduce side effects.

Note: After the Food and Drug Administration (FDA) approves a drug, it tracks and reviews side effects of the medication. Sharing your experience helps make medications safer for everyone by giving doctors and researchers more information about how the drug works in real life. If you develop a side effect while taking fluoxetine and want to tell the FDA about it, visit MedWatch or call 800-FDA-1088.

Mild side effects

Here’s a short list of some of the mild side effects that fluoxetine can cause. To learn about other mild side effects, talk with your doctor or pharmacist, or read the fluoxetine oral capsule’s prescribing information.

Mild side effects of fluoxetine that have been reported include:

  • dry mouth
  • anxiety
  • fatigue or weakness
  • indigestion
  • loss of appetite
  • nausea, vomiting, or diarrhea
  • sexual side effects (see the “Side effect focus” section)
  • hot flashes and sweating more than usual
  • swelling or irritation in your throat and nasal cavity
  • tremors
  • unusual dreams

Mild side effects of many drugs may go away within a few days or a couple of weeks. But if they become bothersome, talk with your doctor or pharmacist.

Serious side effects

Serious side effects from fluoxetine can occur, but they aren’t common. If you have serious side effects from fluoxetine, call your doctor right away. But if you think you’re having a medical emergency, you should call 911 or your local emergency number.

Serious side effects of fluoxetine that have been reported include:

For more information about some of these side effects, see the “Side effect focus” section.

Side effect focus

Learn more about some of the side effects fluoxetine may cause.

Boxed warning

Fluoxetine has boxed warnings. A boxed warning is the most serious warning from the Food and Drug Administration (FDA).

Risk of suicidal thoughts and behaviors in certain people: Like other drugs used to treat depression, fluoxetine may increase the risk of suicidal thoughts and behaviors. Specifically, the drug may increase this risk in people ages 24 years and younger.

This side effect is more likely to occur when you first start taking the medication and any time your doctor adjusts your dosage.

It’s important to note that having depression or another mental health condition is itself a risk factor for suicidal thoughts and behaviors. And fluoxetine is used for some of these conditions.

In studies, antidepressant use didn’t increase the risk of suicidal thoughts and behaviors in people older than age 24 years. And in people ages 65 years and older, these drugs actually decreased this risk.

What might help

If you notice changes in your thoughts or behaviors while you’re taking fluoxetine, call your doctor right away. If you have thoughts of suicide or attempt to harm yourself, get medical attention immediately. You may need to call 911 or your local emergency number.

Your doctor may talk with your family, such as a partner or parent, while you’re taking fluoxetine. They may ask your family to help monitor you for any changes in your thinking or behaviors while you’re taking this drug.

Help is out there

If you or someone you know is in crisis and considering suicide or self-harm, please seek support:

  • Call or text the 988 Suicide and Crisis Lifeline at 988 or chat at 988lifeline.org. Caring counselors are available to listen and provide free and confidential support 24/7.
  • Text HOME to the Crisis Text Line at 741741 to connect with a volunteer crisis counselor for free and confidential support 24/7.
  • Not in the United States? Find a helpline in your country with Befrienders Worldwide.
  • Call 911 or your local emergency services number if you feel safe to do so.

If you’re calling on behalf of someone else, stay with them until help arrives. You may remove weapons or substances that can cause harm if you can do so safely.

If you’re not in the same household, stay on the phone with them until help arrives.

Weight loss

It’s possible to have weight changes while you’re taking fluoxetine. For example, weight loss was reported by people taking the drug in studies. But it was rarely a reason for them to stop taking the drug.

Some people taking fluoxetine may have a higher risk of this side effect. This includes people with depression who are considered underweight, as well as people with bulimia nervosa.

What might help

Talk with your doctor if you’re concerned about weight changes while you’re taking fluoxetine. They can suggest ways to help you maintain a weight that’s healthy for you.

Sexual side effects

You may have sexual side effects with fluoxetine.

Sexual side effects have been reported with other selective serotonin reuptake inhibitors (SSRIs), too.

Sexual side effects reported by people taking fluoxetine in studies include:

It’s important to note that mental health conditions can also cause changes in sexual desire and performance. This includes depression, which fluoxetine is used to treat.

What might help

Talk with your doctor if you have sexual side effects while you’re taking fluoxetine. They may recommend treatment for this side effect. In some cases, they may recommend that you stop taking fluoxetine and try a different medication.

Allergic reaction

Some people may have an allergic reaction to fluoxetine.

Symptoms of a mild allergic reaction can include:

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

A more severe allergic reaction is rare but possible. Symptoms of a severe allergic reaction can include swelling under your skin, typically in your eyelids, lips, hands, or feet. They can also include swelling of your tongue, mouth, or throat, which can cause trouble breathing.

Call your doctor right away if you have an allergic reaction to fluoxetine oral capsules. But if you think you’re having a medical emergency, call 911 or your local emergency number.

Your doctor will explain how you should take fluoxetine. They’ll also explain how much to take and how often. Be sure to follow your doctor’s instructions. The following are commonly used dosages, but always take the dosage your doctor prescribes.

Forms and strengths

Fluoxetine comes in four forms: capsules, delayed-release capsules, tablets, and a liquid solution. Each of these forms is taken by swallowing.

Fluoxetine capsules come in three strengths:

  • 10 milligrams (mg)
  • 20 mg
  • 40 mg

Fluoxetine delayed-release capsules come in one strength: 90 mg

Fluoxetine tablets come in three strengths:

  • 10 mg
  • 20 mg
  • 60 mg

Fluoxetine’s liquid solution is available in one strength: 20 mg per milliliter (mL) of liquid.

Dosage

The fluoxetine dosage your doctor prescribes will depend on your age and the condition you’re taking the drug to manage. The typical recommended daily dosage of fluoxetine can range from 10 to 80 mg.

For MDD, OCD, and bulimia nervosa, it’s recommended you take fluoxetine in the morning. For panic disorder, there’s not a best time of day recommended to take the drug.

Doses of 40 mg and 80 mg are on the high end of fluoxetine’s dosage range. The maximum recommended dose of fluoxetine is 80 mg.

Fluoxetine is typically taken once per day. But depending on your dosage, your prescriber may recommend taking the drug twice per day in divided doses. (This means you may take half your dose in the morning and the other half in the afternoon.)

Fluoxetine delayed-release capsules are taken once per week. If your doctor prescribes this form of fluoxetine, they’ll let you know the best way to take it.

Taking fluoxetine with other drugs

Fluoxetine may be prescribed alone or in combination with other drugs to help manage your condition.

Additionally, fluoxetine comes in a combination pill with the drug olanzapine. This combination pill used to be available as the brand-name drug Symbyax (olanzapine/fluoxetine). Symbyax has been discontinued, but generic olanzapine/fluoxetine is still available.

Olanzapine/fluoxetine is used to treat bipolar I disorder, as well as treatment-resistant depression. (This form of depression doesn’t improve with certain treatments.) Fluoxetine shouldn’t be used by itself to treat these conditions.

Questions about taking fluoxetine

Here’s a list of common questions related to taking fluoxetine.

  • What if I miss a dose of fluoxetine? If you miss a dose of fluoxetine, take it as soon as you remember. But if it’s close to the time to take your next dose, simply skip the missed dose. Then, take your next dose as scheduled. You shouldn’t take an extra dose to try and make up for a missed dose. Doing so can increase your risk of side effects.
  • Will I need to use fluoxetine long term? This depends on decision making between you and your doctor. It also depends on the condition you’re taking fluoxetine to treat. You may take fluoxetine either short term or long term.
  • Can fluoxetine be chewed, crushed, or split? It depends on the form. Fluoxetine capsules are meant to be swallowed whole, but the tablets can be split in half. If you have trouble swallowing tablets or capsules, talk with your doctor. Fluoxetine’s liquid solution may be a better option for you.
  • Should I take fluoxetine with food? Fluoxetine may be taken with or without food.
  • How long does fluoxetine take to work? Like other medications used to treat depression, fluoxetine doesn’t start working right away. It can take 2 to 6 weeks before you notice a reduction in your symptoms. Talk with your doctor or pharmacist if you have more questions about when you’ll see improvement with fluoxetine treatment.

Overdose

Don’t take more fluoxetine than your doctor prescribes. Using more than this can lead to serious side effects.

Symptoms caused by an overdose can include:

What to do in case you take too much fluoxetine

Call your doctor if you think you’ve taken too much fluoxetine. You can also call 800-222-1222 to reach America’s Poison Centers, or use its online resource. But if you have severe symptoms, immediately call 911 (or your local emergency number) or go to the nearest emergency room.

Some important things to discuss with your doctor when considering treatment with fluoxetine include:

  • your overall health
  • any medical conditions you may have
  • any medications you’re taking

These considerations and others are described in more detail in the following sections.

Interactions

Taking medications, vaccines, foods, and other things with a certain drug can affect how the drug works. These effects are called interactions.

Before taking fluoxetine, be sure to tell your doctor about all medications you take, including prescription and over-the-counter types. Also, describe any vitamins, herbs, or supplements you use. Your doctor or pharmacist can tell you about any interactions these items may cause with fluoxetine.

Interactions with drugs or supplements

Fluoxetine can interact with several types of drugs. These drugs include:

This list does not contain all types of drugs that may interact with fluoxetine. Your doctor or pharmacist can tell you more about these interactions and any others that may occur with the use of fluoxetine.

Boxed warning

Fluoxetine has a boxed warning about an increased risk of suicidal thoughts and behaviors in certain people. A boxed warning is the most serious warning from the Food and Drug Administration (FDA).

For more information about this warning, see the “What are fluoxetine’s side effects?” section.

Other warnings

Before taking fluoxetine, discuss your health history with your doctor. Fluoxetine may not be right for you if you have certain medical conditions or other factors affecting your health. Be sure to talk with your doctor if any of the following apply to you:

Pregnancy and breastfeeding

Here’s some information about taking fluoxetine during pregnancy or while breastfeeding.

Use in pregnancy

Studies have shown that when antidepressant drugs such as fluoxetine are used in the third trimester, they can increase the risk of complications at birth.

However, other studies show that people with depression who stop taking their antidepressant during pregnancy are more likely to have their depression symptoms worsen. This is in comparison with people who kept taking their antidepressant.

If you’re pregnant or planning on becoming pregnant, talk with your doctor before taking fluoxetine. They can discuss with you the risks and benefits of using this drug.

Use while breastfeeding

Fluoxetine is known to pass into breast milk. There are reports of side effects in children who are exposed to the drug during breastfeeding. These side effects include agitation and trouble feeding.

Talk with your doctor about the risks and benefits of breastfeeding while taking fluoxetine. They can discuss the safety of breastfeeding versus using other options to feed your child.

Stopping fluoxetine may cause withdrawal symptoms. These symptoms can include:

  • irritability or agitation
  • dizziness
  • anxiety
  • confusion
  • headache
  • problems falling asleep

There have been rare reports of these symptoms being serious in some people.

You’re more likely to have withdrawal symptoms from stopping fluoxetine if you suddenly quit taking the drug. For this reason, you shouldn’t stop taking fluoxetine without talking with your doctor or pharmacist. They can suggest ways to slowly decrease your dose over time.

Fluoxetine (Prozac) and sertraline (Zoloft) are similar, but they also have some differences.

Fluoxetine and sertraline both belong to a group of drugs called selective serotonin reuptake inhibitors (SSRIs). SSRIs are used to treat mental health conditions, such as depression and obsessive-compulsive disorder.

Sertraline is also approved to treat some additional conditions, including social anxiety disorder and post-traumatic stress disorder. Unlike fluoxetine, sertraline isn’t approved to treat bulimia.

Your prescriber can advise whether they recommend fluoxetine or sertraline for your condition.

Whether you have health insurance or not, cost may be a factor when you’re considering fluoxetine. What you’ll pay for fluoxetine may depend on several things, including:

  • your treatment plan
  • the form you’re prescribed
  • the pharmacy you use

You may be able to find drug coupons on prescription discount websites that can reduce the cost of your medication. These coupons cannot be used with insurance copays or benefits, but the discounted price may be lower than what you would pay through insurance.

Q:

I’ve read that fluoxetine stays in your body for a long time. Is it a safe medication for older adults to take for depression?

Anonymous

A:

It depends. Some older adults may have a higher risk of side effects with fluoxetine.

For example, fluoxetine and other antidepressants called selective serotonin reuptake inhibitors (SSRIs), have a greater risk of causing low sodium levels. This is especially true in older people.

If you notice symptoms of a low sodium level, tell your doctor right away. These symptoms may include:

  • headache
  • weakness
  • confusion

Because older people have a higher risk of side effects with this drug, their doctor may have them start taking fluoxetine at a lower dosage than usual. Or their doctor may reduce how often they’ll take the drug.

If you’re concerned about the safety of taking fluoxetine based on your age, talk with your doctor. They can recommend if this drug is right for you.

Melissa Badowski, PharmD, MPH, FCCPAnswers represent the opinions of our medical experts. All content is strictly informational and should not be considered medical advice.

Disclaimer: Healthline 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 other 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.