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Prozac For Anxiety: Benefits, Dosage, Side Effects, and More

Kristin Hall

Medically reviewed by Kristin Hall, FNP

Written by Our Editorial Team

Last updated 7/10/2022

It’s normal to feel anxious from time to time, especially in stressful situations. However, if you’re prone to severe or persistent anxiety, or if you frequently experience panic attacks, you may be one of the tens of millions of American adults with an anxiety disorder.

Several medications are available to treat anxiety disorders, including the antidepressant drug Prozac®.

Prozac, which contains the active ingredient fluoxetine, works by affecting the levels of natural chemicals that control your moods and feelings. Taken consistently, it can help to treat several common forms of anxiety, improving your mental well-being and quality of life.

Below, we’ve explained what Prozac is, as well as how Prozac and similar medications work to treat the symptoms of anxiety

We’ve also explained how you can use Prozac for anxiety, from approved dosages to potential side effects and drug interactions that you should be aware of before you start treatment.

What Is Prozac?

Prozac is an antidepressant that contains the active ingredient fluoxetine. It belongs to a class of drugs called selective serotonin reuptake inhibitors (SSRIs).

The FDA first approved Prozac in 1987 as a medication for treating major depressive disorder (MDD). Prozac is also approved to treat PMDD (premenstrual dysphoric disorder), obsessive-compulsive disorder (OCD), panic disorder, bipolar disorder and bulimia nervosa.

Like many other medications, Prozac is often prescribed off-label to treat conditions other than those approved by the FDA. 

Common off-label uses of Prozac include the treatment of:

  • Social anxiety disorder (SAD, or social phobia)

  • Post-traumatic stress disorder (PTSD)

  • Borderline personality disorder

  • Raynaud phenomenon

  • Selective mutism

As an SSRI, Prozac works by increasing the amount of serotonin — a type of naturally-occurring chemical called a neurotransmitter — that’s active in your brain and body.

Serotonin is involved in regulating your mood, happiness and levels of anxiety. It also plays an important role in regulating your sleep cycle and general mental health. Low levels of serotonin are associated with an increased risk of mental health disorders, including anxiety.

By increasing serotonin levels, Prozac may reduce the severity of anxiety symptoms and make it easier for you to maintain a normal life.

Does Prozac Help With Anxiety?

Prozac doesn’t treat every form of anxiety, but it can provide real benefits for people with certain anxiety conditions. 

Prozac is approved by the FDA to treat panic disorder — a common type of anxiety disorder that involves intense periods of fear, discomfort and loss of control called panic attacks.

It’s also commonly used as an off-label treatment for social anxiety disorder — another common anxiety disorder that involves intense, persistent fears in social situations, such as public events and auditions. 

Prozac isn’t a cure for anxiety, and using it doesn’t guarantee that you’ll never have to deal with panic attacks, intrusive thoughts, compulsive behavior or other problems again. Nor is it always the best treatment option for every type of anxiety disorder.

However, when it’s taken appropriately and consistently, Prozac may make it easier to manage some anxiety and major depression symptoms.

Over the decades, numerous studies have looked at the effects of Prozac as a treatment option for anxiety. 

During clinical trials, researchers found that Prozac significantly increased the number of people with panic disorder who reported an end to their panic attacks.

In one randomized trial involving 180 participants, Prozac produced a significant increase in the number of people who were free of panic attacks after 12 weeks (42 percent, versus 28 percent for a non-therapeutic placebo).

A similar flexible-dose trial involving 214 people produced similar findings, with 62 percent of the participants experiencing an end to panic attacks while using Prozac compared to 44 percent of people who used a non-therapeutic placebo.

Research into the effectiveness of Prozac for other forms of anxiety is mixed, with some studies showing positive effects and others showing limited changes:

  • One study of fluoxetine (the active ingredient in Prozac) for social anxiety published in the journal Archives of General Psychiatry concluded that it was more effective than a placebo and comparable to cognitive behavioral therapy (CBT).

  • A general meta-analysis of selective serotonin reuptake inhibitor medications (SSRIs) and social anxiety found that medications of this type, including Prozac, can offer real benefits, including improved scores in certain social functioning scales.

  • However, a double-blind, placebo-controlled study involving 60 people published in the Journal of Clinical Psychopharmacology found that Prozac was no more effective than placebo treatments for social phobia.

  • A small trial published in the Journal of the American Academy of Child and Adolescent Psychiatry in 2003 found that fluoxetine was effective and well-tolerated as a treatment for generalized anxiety, separation anxiety disorder and social phobia in youths.
    However, this study only involved individuals from seven to 17 years of age, and did not feature any adult participants. 

  • A literature review of Chinese patients published in the journal Neuropsychiatric Disease and Treatment in 2013, which used data from 15 open-label, non-placebo trials, stated that Prozac was comparable in efficacy to other anxiety medications.
    However, the researchers noted that existing research on Prozac for anxiety has a high risk of bias, and that small sample sizes and a lack of placebo groups make it difficult to draw any firm conclusions from existing studies.

Overall, there’s strong evidence that Prozac is helpful for panic disorder, with mixed findings on its potential benefits for social anxiety, generalized anxiety disorder and other forms of anxiety. 

How Quickly Does Prozac Work for Anxiety?

Prozac is generally an effective medication for social anxiety, post-traumatic stress disorder and other conditions that involve anxiety. However, it doesn’t deliver instant relief, meaning you won’t feel calm and relaxed right away. 

It can take four to five weeks for Prozac to start working fully. During this time, you may begin to experience small, gradual improvements in some anxiety symptoms, including your feelings and general moods.

It’s important to not to stop taking Prozac if you don’t notice improvements during the first four to five weeks. Be patient and keep using Prozac — over time, you’ll start to notice improvements as the medication becomes more effective.

Prozac Dosage for Anxiety

Prozac is typically prescribed at a dosage of 10 to 20mg daily for panic disorder and 20mg per day for obsessive-compulsive disorder. Your healthcare provider may adjust this dosage over time based on your response to Prozac, your risk of side effects and other factors. 

Most people respond well to Prozac at a dosage of 20 to 40mg daily. The maximum dosage of Prozac is 80mg per day.

There’s currently no precise dosage of Prozac for off-label uses, such as obsessive-compulsive disorder or social anxiety disorder. 

If you’re prescribed Prozac for off-label use, your healthcare provider may instruct you to start at a low dosage, then adjust your dosage over time. 

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Prozac Side Effects and Interactions

Like other antidepressants, Prozac can cause side effects. It’s important to let your healthcare provider know if you have any side effects that are severe, bothersome or do not improve over time.

Common side effects of Prozac include:

  • Abnormal dreams

  • Anorexia

  • Anxiety

  • Asthenia (physical weakness)

  • Diarrhea

  • Dry mouth

  • Dyspepsia (indigestion)

  • Flu symptoms

  • Insomnia

  • Nausea

  • Nervousness

  • Pharyngitis (sore throat)

  • Rash

  • Sinusitis

  • Somnolence (drowsiness)

  • Sweating

  • Tremor

  • Vasodilation

  • Yawning

Many adverse effects of Prozac improve gradually as your body starts to adjust to the effects of this medication. 

Like other SSRIs, Prozac can cause sexual side effects, including sexual dysfunction in women and men. While using Prozac, you may notice that your sex drive is weaker than normal, or that you find it more difficult to reach orgasm during sexual activity.

Prozac can interact with other medications. When used with medications that increase serotonin levels, Prozac may cause a potentially dangerous drug interaction called serotonin syndrome, in which serotonin levels increase beyond a safe level.

Serotonin syndrome can cause serious, potentially harmful symptoms, including elevated blood pressure, heart palpitations, tremor, shivering, muscle jerking and overly active reflexes. Severe cases of serotonin syndrome may cause renal failure, blood clots, coma and even death.

Medications and supplements that may interact with Prozac include:

  • Tricyclic antidepressants (TCAs)

  • Monoamine oxidase inhibitors (MAOIs)

  • SSRIs and other antidepressants

  • Fentanyl, tramadol and other opioid pain medications

  • Anxiety medications, such as buspirone (Buspar®)

  • Amphetamines

  • St. John’s wort

  • Tryptophan

To reduce your risk of experiencing serotonin syndrome or other drug interactions, make sure to inform your healthcare provider about any medications you currently take or have recently taken before starting treatment with Prozac.

It’s especially important to inform your healthcare provider if you’ve used an MAOI or other type of antidepressant medication to treat any medical conditions within the last 14 days.

If you're concerned about an interaction with your ADHD medication, you can read our blog on Prozac and Adderall.

How to Use Prozac for Anxiety

Prozac is an easy medication to use. It’s available as a capsule, a tablet and as a solution. Most people take Prozac one time each day in the morning. Your healthcare provider will inform you about when to take Prozac and how much medication to take each day. 

Use the following tips to get the best results from Prozac as an anxiety treatment:

  • Take Prozac at around the same time every day. Prozac works best when it’s taken at a consistent time of day. Try to follow your healthcare provider’s instructions as closely as you can and aim to take Prozac at around the same time daily.

  • If you miss a dose, take it as soon as you remember. However, if it’s almost the right time for your next dose of Prozac, skip the missed dose and continue as normal. Do not take two doses of Prozac at once to make up for a missed dose.

  • Combine Prozac with psychotherapy. Prozac and other antidepressants often have a greater effect when they’re combined with certain forms of talk therapy, such as cognitive behavioral therapy (CBT).
    Your healthcare provider may recommend meeting with a therapist. We also offer online therapy, allowing you to connect with a licensed provider from the privacy and comfort of your home. 

  • Wait two to four weeks before assessing your results from Prozac. It usually takes two to four weeks for Prozac to start working properly, during which you may not notice any improvements in your moods, feelings or anxiety symptoms.
    When you start taking Prozac, be patient. Try to wait for at least four weeks before you start assessing your results. 

  • If Prozac doesn’t work for you, don’t worry. It’s normal to try several antidepressants before finding the right one for you. If Prozac doesn’t seem to work well for you after two to four weeks, don’t panic. Instead, let your healthcare provider know.
    Your healthcare provider may adjust your dosage or recommend switching to a different antidepressant or anti-anxiety medication that’s better suited to your needs.

  • Never stop taking Prozac abruptly. When Prozac is stopped abruptly, it can potentially cause withdrawal symptoms, including mood changes, dizziness, agitation, sleep issues, headaches and a return of your anxiety symptoms.
    If Prozac isn’t working, don’t stop taking it abruptly. Instead, let your healthcare provider know that you’d like to stop treatment. They’ll help you to slowly taper your dosage and stop using Prozac safely.

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Learn More About Treating Anxiety

Prozac is a popular, effective medication for treating panic disorder, a common form of anxiety that can involve sudden panic attacks. However, research findings are mixed when it comes to using Prozac for social anxiety or generalized anxiety disorder.

If you’re prescribed Prozac for anxiety, make sure to closely follow your mental health provider’s instructions and inform them if you experience any side effects.

Interested in learning more about dealing with anxiety? We offer a full range of medications for anxiety and depression online, which are available following a private online consultation with a psychiatry provider who will determine if a prescription is appropriate.

We also offer other mental health services, including individual online therapy and anonymous online support groups

You can also learn more about successfully coping with anxiety, depression, severe stress and other mental health concerns using our free online mental health resources and content.

10 Sources

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.

  1. PROZAC (fluoxetine capsules) for oral use. (2017, January). Retrieved from https://www.accessdata.fda.gov/drugsatfda_docs/label/2017/018936s108lbl.pdf
  2. Sohel, A.J., Shutter, M.C. & Molla, M. (2022, May 2). Fluoxetine. StatPearls. Retrieved from https://www.ncbi.nlm.nih.gov/books/NBK459223/
  3. Brain Hormones. (2022, January 23). Retrieved from https://www.endocrine.org/patient-engagement/endocrine-library/hormones-and-endocrine-function/brain-hormones
  4. Davidson, J.R., et al. (2004, October). Fluoxetine, comprehensive cognitive behavioral therapy, and placebo in generalized social phobia. Archives of General Psychiatry. 61 (10), 1005-1013. Retrieved from https://pubmed.ncbi.nlm.nih.gov/15466674/
  5. Hedges, D.W., et al. (2007, January). The efficacy of selective serotonin reuptake inhibitors in adult social anxiety disorder: a meta-analysis of double-blind, placebo-controlled trials. Journal of Psychopharmacology (Oxford, England). 21 (1), 102-111. Retrieved from https://pubmed.ncbi.nlm.nih.gov/16714326/
  6. Kobak, K.A., Greist, J.H., Jefferson, J.W. & Katzelnick, D.J. (2002, June). Fluoxetine in social phobia: a double-blind, placebo-controlled pilot study. Journal of Clinical Psychopharmacology. 22 (3), 257-262. Retrieved from https://pubmed.ncbi.nlm.nih.gov/12006895/
  7. Birhamer, 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 https://pubmed.ncbi.nlm.nih.gov/12649628/
  8. 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 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3818099/
  9. Volpi-Abadie, J., Kaye, A.M. & Kaye, A.D. (2013). Serotonin Syndrome. The Ochsner Journal. 13 (4), 533-540. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3865832/
  10. Anxiety Disorders. (2022, April). Retrieved from https://www.nimh.nih.gov/health/topics/anxiety-disorders

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.

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