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Prozac (Fluoxetine) for Anxiety

Kristin Hall, FNP

Reviewed by Kristin Hall, FNP

Written by Nicholas Gibson

Published 06/02/2022

Updated 05/03/2022

Every year, tens of millions of American adults are affected by anxiety disorders such as social anxiety disorder, panic disorder and generalized anxiety disorder (GAD).

If you’ve been diagnosed with an anxiety disorder, your mental health provider may prescribe a type of anti-anxiety medication to help you control your symptoms and enjoy a higher quality of life.

Prozac®, which contains the active ingredient fluoxetine, is an antidepressant that’s often used to treat anxiety disorders.

Below, we’ve explained what Prozac is, as well as how it works as a treatment for certain forms of anxiety. 

We’ve also covered the basics of using Prozac for anxiety, from typical dosages to side effects, drug interactions and more.

Prozac is a common brand name for fluoxetine, an antidepressant that’s part of a class of drugs calledselective serotonin reuptake inhibitors (SSRIs).

Fluoxetine, the active ingredient in Prozac, was first approved by the FDA in the late 1980s as a treatment for depression. Like most other SSRIs, Prozac is currently available under its original brand name and in generic form as fluoxetine.

As an SSRI, Prozac works by increasing the amount of serotonin — a natural chemical referred to as a neurotransmitter — in your brain and body.

Serotonin plays an important role in regulating your moods, including feelings of happiness and anxiety. Low levels of serotonin are associated with anxiety, obsessive-compulsive disorder and depression, as well as other behavioral and emotional issues.

Experts believe that medications like Prozac help to treat anxiety by increasing serotonin levels and promoting a more balanced mood and mental state.

Currently, Prozac and generic fluoxetine are approved by the FDA to treat panic disorder, major depressive disorder (MDD), obsessive-compulsive disorder (OCD), bipolar disorder and certain eating disorders, such as bulimia nervosa and binge eating disorder.

Although Prozac isn’t approved by the FDA specifically as an anxiety medication, it’s commonly used off-label as a treatment for social anxiety disorder (SAD, or social phobia), post-traumatic stress disorder (PTSD) and other mental health conditions that involve anxiety symptoms.

Although Prozac wasn’t originally designed as an anxiety medication, research generally shows that it’s effective as a treatment for some anxiety disorders.

This is also true for many other antidepressants, which were originally developed to treat major depression but are widely used as anxiety medications. 

In a review published in the journal Neuropsychiatric Disease and Treatment, researchers used data from 15 open-label, non-placebo trials to analyze the effects of fluoxetine (the ingredient in Prozac) as a treatment for generalized anxiety disorder.

They found that fluoxetine was equally as effective as other anti-anxiety medications and had a lower risk of causing side effects than drugs like amitriptyline (an older tricyclic antidepressant) and diazepam (a benzodiazepine).

However, due to the limited quality of the research data, they stopped short of recommending fluoxetine as a treatment for anxiety.

Another large-scale review concluded that fluoxetine is an effective medication for managing obsessive-compulsive disorder. 

One small study from the early 2000s looked at the effects of fluoxetine as a potential anxiety treatment in children and teens with generalized anxiety disorder, separation anxiety disorder and social anxiety.

The researchers found that fluoxetine was more effective than a non-therapeutic placebo as a treatment for generalized anxiety disorder and social phobia, and that the medication was well tolerated by the participants in the study. 

Our guide to using antidepressants for anxiety goes into more detail about how SSRIs such as fluoxetine can help to treat anxiety disorders.

Whether you take brand-name Prozac or generic fluoxetine, using fluoxetine to treat anxiety is generally a straightforward process.

Fluoxetine is available as a capsule, tablet or oral solution (liquid). Your mental health provider will generally prescribe fluoxetine for use either one time per day in the morning or twice a day in the morning and at midday.

For panic disorder, fluoxetine is usually prescribed at an initial dosage of 10mg per day. Your mental health provider may adjust your dosage based on the severity of your panic symptoms and your response to fluoxetine.

For obsessive-compulsive disorder, fluoxetine is usually prescribed at a dosage of 20mg daily, taken in the morning. This may also be adjusted over time based on your needs and general response to treatment.

Since fluoxetine isn’t FDA-approved for social anxiety disorder, post-traumatic stress disorder and other conditions, the FDA doesn’t provide specific dosage instructions for these uses. As such, there’s no single fluoxetine dosage for anxiety

If you’re prescribed fluoxetine off-label to treat social anxiety, PTSD or other anxiety disorders, your mental health provider will choose an appropriate dose based on your anxiety symptoms and personal needs. 

Fluoxetine may take four to five weeks to start working. If you’re prescribed fluoxetine to treat a form of anxiety, make sure to continue using it even if you don’t feel any improvements in the first few weeks. Talk to your healthcare provider if you don’t feel better after five weeks of use.

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Side Effects of Prozac (Fluoxetine)

Fluoxetine is generally a safe and effective medication. However, like other antidepressants, it can cause adverse side effects. Common side effects of fluoxetine include:

  • Insomnia

  • Nausea

  • Yawning

  • Diarrhea

  • Anxiety

  • Nervousness

  • Headache

  • Drowsiness

  • Dry mouth

  • Hyperhidrosis (abnormal, excessive sweating)

  • Weight gain or weight loss

  • Pharyngitis (sore throat)

  • Mania symptoms

  • Muscle weakness

  • Tremors

Like other antidepressants, Prozac and generic fluoxetine can cause sexual side effects, such as a reduction in your sex drive, changes in your level of sexual arousal and difficulty reaching orgasm and ejaculating during sex.

Most of the potential side effects of fluoxetine occur during the first few weeks of treatment and gradually get better. If you develop side effects, your mental health provider may recommend waiting before making changes to your dosage or switching medications.

Although uncommon, fluoxetine may cause more severe side effects. Contact your healthcare provider as soon as possible if you develop any of the following adverse effects or signs of an allergic reaction:

  • Skin rash, hives, itching or blisters

  • Swelling that affects your face, lips, tongue, throat, eyes or extremities

  • Feelings of agitation, hallucinations or a loss of coordination

  • Difficulty swallowing and/or breathing

  • A slow, fast or irregular heartbeat

  • Abnormal bleeding or bruising

  • Muscle stiffness and/or twitching

  • Shortness of breath

  • Dizziness or fainting

  • Confusion

  • Shivering

  • Seizures

Prozac (Fluoxetine) Drug Interactions

Prozac and generic fluoxetine can interact with other medications, including prescription drugs, medications available over the counter and certain dietary supplements.

Like other antidepressants, Prozac can cause a serious issue called serotonin syndrome when it’s used with other medications that increase serotonin levels. Some medications may remain in your system for several weeks and interact with Prozac, even without daily use. 

To keep yourself safe while using Prozac or generic fluoxetine, tell your mental health provider about all medications you currently use or have recently used, including all antidepressants or similar medications you’ve used within the last 14 days.

Prozac can cause issues when it’s used with alcohol. Avoid drinking alcohol while you’re using brand name Prozac, generic fluoxetine or other medications to treat depression or anxiety. 

Prozac (Fluoxetine) and Suicidal Ideation

Many antidepressants, including SSRIs such as fluoxetine, are associated with an elevated risk of suicidal thoughts and behavior in children, teens and young adults. These medications carry a “black box” warning from the FDA notifying users of these risks.

If you’re prescribed Prozac or generic fluoxetine, your healthcare provider will inform you about the risks of suicidal ideation and behavior. Make sure to contact your mental health provider or seek urgent medical care if you develop suicidal thoughts while using Prozac.

Prozac (Fluoxetine) Withdrawal Symptoms

Prozac and generic fluoxetine can cause withdrawal symptoms such as irritability, anxiety, mood changes and physical issues if stopped suddenly. 

If you’re prescribed fluoxetine for anxiety, depression or any other condition and no longer want to keep using it, talk to your mental health provider before making any changes to your dosage or stopping your medication.

Your mental health provider will help you to safely stop taking fluoxetine by gradually adjusting your dosage.

Fluoxetine isn’t the only selective serotonin reuptake inhibitor that’s used to treat anxiety. Other SSRIs used to treat anxiety include paroxetine (Paxil®), escitalopram (Lexapro®), fluvoxamine (Luvox® CR) and sertraline (Zoloft®).

Currently, there’s very little high-quality research that compares fluoxetine to sertraline when it comes to anxiety. However, one study from the 1990s found that both medications had similar effects in people with major depression, including on several anxiety rating scales.

Sertraline is approved by the FDA to treat obsessive-compulsive disorder, panic disorder and social anxiety disorder, as well as premenstrual dysphoric disorder (PMDD) and depression.

Our guide to sertraline goes into more detail about how it works as a treatment for depression and anxiety disorders, as well as what you should know before using sertraline.

Prozac and generic fluoxetine are commonly used to treat several anxiety disorders, including panic disorder, social anxiety disorder and obsessive-compulsive disorder.

If you’re prescribed fluoxetine for anxiety, it may take a few weeks to begin working. Make sure to keep in contact with your mental health provider while using fluoxetine, and let them know if you develop any side effects.

If you need help with anxiety, you can connect with a licensed psychiatry provider online using our psychiatry services. You can also access online therapy, support groups and other types of care with our full range of online mental health services

Want to learn more about your options for treating anxiety? Our complete guide to anti-anxiety medications covers everything you need to know about using medication to treat anxiety, from short-acting drugs to longer-term solutions. 

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  6. Zou, C., Ding, X., Flaherty, J.H. & Dong, B. (2013). Clinical efficacy and safety of fluoxetine in generalized anxiety disorder in Chinese patients. Neuropsychiatric Disease and Treatment. 9, 1661-1670. Retrieved from
  7. Rossi, A., Barraco, A. & Donda, P. (2004). Fluoxetine: a review on evidence based medicine. Annals of General Hospital Psychiatry. 3, 2. Retrieved from
  8. Birmaher, B., et al. (2003, April). Fluoxetine for the treatment of childhood anxiety disorders. Journal of the American Academy of Child and Adolescent Psychiatry. 42 (4), 415-423. Retrieved from
  9. Aguglia, E., et al. (1993). Double-blind study of the efficacy and safety of sertraline versus fluoxetine in major depression. International Clinical Psychopharmacology. 8 (3), 197-202. Retrieved from
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Hims & Hers has strict sourcing guidelines to ensure our content is accurate and current. We rely on peer-reviewed studies, academic research institutions, and medical associations. We strive to use primary sources and refrain from using tertiary references. See a mistake? Let us know at [email protected]!

This article is for informational purposes only and does not constitute medical advice. The information contained herein is not a substitute for and should never be relied upon for professional medical advice. Always talk to your doctor about the risks and benefits of any treatment. Learn more about our editorial standards here.

Kristin Hall, FNP

Kristin Hall is a board-certified Family Nurse Practitioner with decades of experience in clinical practice and leadership. 

She has an extensive background in Family Medicine as both a front-line healthcare provider and clinical leader through her work as a primary care provider, retail health clinician and as Principal Investigator with the NIH

Certified through the American Nurses Credentialing Center, she brings her expertise in Family Medicine into your home by helping people improve their health and actively participate in their own healthcare. 

Kristin is a St. Louis native and earned her master’s degree in Nursing from St. Louis University, and is also a member of the American Academy of Nurse Practitioners. You can find Kristin on LinkedIn for more information.

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