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Prozac side effects: A detailed guide

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Prozac is prescribed for certain mental health conditions. It’s a selective serotonin reuptake inhibitor (SSRI) that may cause mild or serious side effects. These include weight loss and risk of suicidal thoughts and behaviors.
Medically reviewed by Alex Brewer, PharmD, MBA
Updated on August 26, 2023

Specifically, the Food and Drug Administration (FDA) has approved Prozac to treat:

This article describes possible side effects of Prozac. You’ll also find information on cost savings and coupon options for Prozac. You can explore this overview article to learn more about Prozac, including the drug’s uses, side effects, and more.

Prozac is a brand-name medication that comes as an oral capsule. It’s available in a generic version called fluoxetine.

* For this use, Prozac is taken with olanzapine (Zyprexa).

Boxed warning: Risk of suicidal thoughts and behaviors

Prozac has a boxed warning for the risk of suicidal thoughts and behaviors in certain people. A boxed warning is the most serious warning from the FDA.

For details, see the “Side effects of Prozac in detail” section below.

More common side effects of Prozac

Prozac may cause mild or serious side effects. Below are some of the more common side effects of this medication.

Commonly reported side effects of Prozac include:

Mild side effects of Prozac

Prozac may cause certain mild side effects. Most often, mild side effects are temporary and can be easily managed. Tell your doctor or pharmacist if you have side effects that don’t go away or become bothersome.

Mild side effects of Prozac that occurred in studies include:

Prozac may cause more mild side effects than those listed above. For details, see the drug’s prescribing information.

* To learn more about this side effect, see the “Side effects of Prozac in detail” section below.

Serious side effects of Prozac

Prozac may cause certain serious side effects. If you have any serious side effects from Prozac, call your doctor right away. But if you think you’re having a medical emergency or your side effects feel life threatening, take immediate action. Call 911 or a local emergency number, or go to the nearest emergency room.

After the Food and Drug Administration (FDA) approves a drug, it tracks and reviews side effects of the medication. Visit MedWatch’s website if you’d like to notify the FDA about a side effect you’ve had with Prozac.

Serious side effects of Prozac that occurred in studies include:

* This side effect wasn’t reported in studies of Prozac. But it has occurred in people after the drug was approved for use.
† To learn more about this side effect, see the “Side effects of Prozac in detail” section below.
Prozac has a boxed warning for this side effect. A boxed warning is the most serious warning from the FDA. To learn more, see the “Side effects of Prozac in detail” section below.

Side effects of Prozac in children

For children, doctors prescribe Prozac to treat the following conditions:

* For this use, Prozac is taken with olanzapine (Zyprexa).

In studies, side effects in children were generally similar to those in adults. The following side effects were also reported in children:

Prozac also has a boxed warning for risk of suicidal thoughts and behaviors. A boxed warning is the most serious warning from the Food and Drug Administration (FDA). This risk affects children and adults younger than age 24 years. For details, see the “Side effects of Prozac in detail” section below.

If you’d like to know more about side effects in children taking Prozac, talk with your doctor or pharmacist.

Common questions about side effects of Prozac

Here are answers to some common questions about side effects of Prozac. If you have other questions, talk with your doctor or pharmacist.

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

For the most part, side effects of Prozac in females* are similar to those reported in males.* However, there are a few exceptions.

Specifically, sexual side effects of Prozac may differ in females and males. For details about this, see the “Side effects of Prozac in detail” section below. In addition, heavy menstrual bleeding has been reported in female children taking Prozac.

If you have other questions about this, talk with your doctor or pharmacist.

* Sex and gender exist on spectrums. In this article, we use the terms “male” and “female” to refer to a person’s sex assigned at birth.

Does Prozac cause long-term side effects?

Yes, in some cases Prozac may cause long-term side effects. These can occur if you take the drug for a long time. Or they may last for a while after you’ve stopped taking the drug.

Examples of long-term side effects reported with Prozac include:

Talk with your doctor to learn more about these side effects and how to manage them. Ask your doctor for more information about how long these side effects of Prozac may last.

* To learn more about this side effect, see the “Side effects of Prozac in detail” section below.

Can side effects of Prozac change week by week?

It’s possible, particularly during the first several weeks of Prozac treatment.

This is because your doctor may start by prescribing a low dosage of Prozac. Then they may increase your dosage over time until the drug gives the desired outcome. During this time, you may have side effects from Prozac as your body adjusts to the drug.

There’s another possible reason that side effects of Prozac may change week by week during the first several weeks of treatment. When you first start taking the drug, it takes a long time for the level of Prozac in your system to become steady. So it’s possible you may not have side effects until several weeks after you start taking it.

Usually, side effects of Prozac are short term and go away on their own. But the drug may cause certain long-term side effects in some cases. See the question above to learn more.

Talk with your doctor or pharmacist if you have other questions about what to expect with Prozac week by week.

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Do side effects of Prozac go away?

Yes, most side effects of Prozac go away within a few days or weeks after starting or stopping the drug. However, in some cases, Prozac may cause side effects that last longer. See the “Does Prozac cause long-term side effects?” question above to learn more.

Talk with your doctor or pharmacist if you have bothersome or long lasting side effects with Prozac. They can tell you more about what to expect during Prozac treatment.

Coupon for Prozac

Visit this page to access Optum Perks coupons and get price estimates for Prozac when you use the coupons. These coupons can provide significant savings on your prescription costs. 

Note: Optum Perks coupons cannot be used with insurance copays or benefits.

Side effects of Prozac in detail

Below you’ll find details on some of the side effects of Prozac.

Risk of suicidal thoughts and behaviors

Prozac has a boxed warning for risk of suicidal thoughts and behaviors. A boxed warning is the most serious warning from the Food and Drug Administration (FDA). This risk affects children and adults younger than age 24 years.

In studies, suicidal behaviors were rare in people taking Prozac. This side effect may be serious.

With suicidal thoughts or behaviors, you may have thoughts of harming yourself. Other symptoms may include feeling restless, angry, anxious, or depressed.

Keep in mind that conditions Prozac is used to treat, such as depression, may also increase risk of suicidal thoughts or behaviors. Other factors that can increase this risk include being in the first few months of Prozac treatment and having your Prozac dosage changed.

Ways to manage

If you have thoughts of harming yourself, call the Suicide and Crisis Lifeline at 988. You can also call 911 or your local emergency number.

If you have symptoms of suicidal thoughts or behaviors while taking Prozac, tell your doctor right away. They can recommend whether it’s safe to continue Prozac treatment.

Suicide prevention

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

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 are not in the same household, stay on the phone with them until help arrives.

Weight loss

In studies, weight loss was rare in people taking Prozac. This side effect is usually mild but may be serious.

Keep in mind that Prozac may also cause loss of appetite as a side effect, which could lead to weight loss.

Ways to manage

If you have concerns about weight loss with Prozac, tell your doctor. They can recommend ways to help you maintain a weight that’s healthy for you.

Sexual side effects

Sexual side effects were common in studies of people taking Prozac. These side effects may be serious.

With sexual side effects, females* may experience low sex drive, inability to orgasm, or delayed orgasm. Males* may experience abnormal ejaculation, low sex drive, and erectile dysfunction.

Keep in mind that conditions Prozac is used to treat, such as depression, may also cause sexual problems.

* Sex and gender exist on spectrums. In this article, we use the terms “male” and “female” to refer to a person’s sex assigned at birth.

Ways to manage

If you have sexual side effects with Prozac, tell your doctor. They’ll help you decide whether Prozac or another factor could be the cause. Your doctor can also recommend treatments other than Prozac for your condition.

Allergic reaction

For some people, Prozac can cause an allergic reaction.

Symptoms can be mild or serious, and they may include:

  • itchiness
  • skin rash
  • swelling under the skin, usually affecting eyelids, lips, hands, or feet
  • swelling of the mouth, tongue, or throat, which can make it hard to breathe
  • flushing (temporary warmth, redness, or deepening of skin color)

Ways to manage

For mild allergic reaction symptoms, such as a mild rash, call your doctor right away. They may recommend treatments to help manage your symptoms. They’ll also let you know whether you should keep taking the medication.

For severe allergic reaction symptoms, such as swelling or trouble breathing, call 911 or your local emergency number right away. These symptoms require immediate medical care because they can become life threatening. If you’ve had a serious allergic reaction to Prozac, your doctor may recommend taking a different medication instead.

Warnings for Prozac

Below are some factors you may want to discuss with your doctor before taking Prozac.

Boxed warning: Risk of suicidal thoughts and behaviors

Prozac has a boxed warning for the risk of suicidal thoughts and behaviors. A boxed warning is the most serious warning from the Food and Drug Administration (FDA).

For details, see the “Side effects of Prozac in detail” section above.

Other warnings

It may not be safe for you to take Prozac if you have specific health conditions. These are sometimes called drug-condition interactions. Other things may also affect whether Prozac is a safe treatment option for you.

Before taking Prozac, tell your doctor about your health and medications you take. Things to consider include:

Prozac and pregnancy

It’s not known whether Prozac should be taken during pregnancy. If you’re planning a pregnancy or can become pregnant, talk with your doctor before taking this medication.

If you take Prozac during pregnancy, your doctor may recommend that you join the drug’s pregnancy registry. This registry collects information about the risks and benefits of taking Prozac while pregnant. To learn more, talk with your doctor. You can also visit the registry website or call 844-405-6185.

Prozac and breastfeeding

It’s not known whether Prozac should be taken while breastfeeding. The drug passes into breast milk and may cause side effects in children who are breastfed. Examples of these side effects include agitation, irritability, and poor weight gain.

If you’re currently breastfeeding or planning to do so, talk with your doctor before taking this medication.

Prozac and alcohol

Prozac is known to interact with alcohol. Drinking alcohol while taking Prozac may worsen certain side effects of the drug, such as sleepiness and nausea.

If you drink alcohol, talk with your doctor about whether it’s safe to consume it during your treatment with Prozac.

What to ask your doctor

This article describes common and serious side effects of Prozac. If your doctor prescribes this medication, they can discuss possible side effects with you. Let your doctor know if you have concerns or questions about treatment with this medication.

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

  • How do the side effects of Prozac compare with those of other drugs used to treat mental health conditions?
  • Do I take any medications that interact with Prozac and raise my risk of side effects?
  • Does my health history raise my risk of side effects from Prozac?

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.

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