Prozac for Anxiety Disorders

Side Effects, Interactions, and Risks

Possible Effects of Prozac

Verywell / Cindy Chung 

What Is Prozac?

Prozac (fluoxetine) is an antidepressant that was first introduced in the United States to treat depression in the 1980s. It is part of a class of medications known as selective serotonin reuptake inhibitors (SSRIs).

Prozac is mainly used to treat major depression, obsessive-compulsive disorder, and panic disorder (all of which are FDA-approved uses), but it is also sometimes used off-label to treat other anxiety disorders.

This article discusses how Prozac works and what you should know before taking it. It also covers potential side effects, interactions, withdrawal symptoms, and other medications you might consider.

How Prozac Works

As an SSRI, Prozac works by preventing the brain from reabsorbing naturally occurring serotonin. Serotonin is involved in mood regulation. In this way, Prozac helps the brain to maintain enough serotonin so that you have a feeling of well-being, resulting from improved communication between brain cells.

Research also highlights how medications such as Prozac may help in combination with psychotherapy. In a 2008 mice study published in Science, it was shown that Prozac helped the brain to enter a more immature and plastic state, possibly making it easier for therapy to have an effect.

Studies like this have provided insight into why combining medication such as Prozac with talk therapy can be effective for anxiety.

What It Feels Like to Take Prozac

If you experience a positive response to Prozac, you might notice a decrease in your anxiety symptoms and feel more like yourself again:

  • More relaxed
  • Less anxious
  • Improved sleep and appetite
  • Greater interest in life
  • Increased energy
  • Improved focus

Remember that it may take time for these improvements to become noticeable—even up to 12 weeks in some cases. You may also experience side effects at first, so it may be hard to notice the improvements until the side effects lessen.

Using Prozac for Anxiety

Prozac is believed to be effective for relieving symptoms of some anxiety disorders, particularly panic disorder. Prozac is often considered a first-line treatment for anxiety disorders. However, there are a number of steps involved in getting a prescription. Generally, you must be diagnosed with a mental health disorder by a healthcare provider before you would be prescribed Prozac or any other prescription treatment.

While a family doctor is qualified to write a prescription, the process is better handled by a mental health professional with experience in mental health disorders who can also prescribe medication, such as a psychiatrist.

Dosage and Administration

Prozac is usually prescribed at a low dose to start, and then gradually increased to 20 mg per day. The maximum dose is 80 mg a day. It can be taken as a liquid or capsule and should be used as prescribed. It can take several weeks for effects to show, so it is important not to stop taking Prozac abruptly even if you think it is not working.

Only take the medication as prescribed by a doctor or psychiatrist. Stopping cold turkey could be dangerous and cause withdrawal symptoms.

Side Effects of Prozac

Some side effects of Prozac are more likely than others. Some people notice that side effects lessen over time, or become less bothersome.

Common side effects include:

  • Anxiety
  • Blurred vision
  • Diarrhea
  • Dizziness
  • Dry mouth
  • Fatigue
  • Headaches
  • Heartburn
  • Loss of appetite
  • Lightheadedness
  • Nausea
  • Sleep problems
  • Sexual problems
  • Sweating
  • Yawning

Rare side effects include:

  • Bleeding or bruising
  • Extreme anxiety
  • Feeling confused
  • Fever
  • Vomiting
  • Seizures
  • Rash/hives
  • Suicidal thoughts or behavior
  • Swelling
  • Trouble breathing or swallowing

If you experience any of these severe side effects while taking Prozac, be sure to notify a doctor or psychiatrist.

Precautions Before Taking Prozac

There has been some controversy about the safety of Prozac, due to the issuing of a safety warning by the Food and Drug Administration (FDA) in 2007 about the risk for suicidal thoughts among certain groups.

Despite this warning, Prozac continues to be prescribed and can be used safely (or discontinued if adverse effects develop) when under the guidance of a physician. If you have concerns about the safety of taking Prozac, discuss them with a doctor.

Medication and Drug Interactions

Prozac should not be combined with monoamine oxidase inhibitors (MAOIs) or taken within 14 days of discontinuing an MAOI. You should also allow at least five weeks after stopping Prozac before starting an MAOI.

The use of pimozide and thioridazine also increases the risk involved in taking Prozac. The result of medication interactions can be serious and potentially fatal, so you should discuss all medications you are taking with a doctor or psychiatrist to determine whether potential interactions exist.

Prozac should not be combined with alcohol, certain over-the-counter (e.g., aspirin, due to the risk of bleeding) and prescription medications, and nutritional supplements or herbs (e.g., St. John's Wort). Be sure to tell your prescribing physician about everything that you are taking.

Prozac should not be taken at the same time as monoamine oxidase inhibitors (MAOIs), the antipsychotics pimozide and thioridazine, tricyclic antidepressants (TCAs), or drugs metabolized by CYP2D6. Care should also be taken if using drugs that affect the central nervous system (CNS), such as benzodiazepines.


Taking Prozac with other medications or supplements can lead to drug interactions. Always tell your doctor about any other medications you are taking before you begin taking Prozac for anxiety.

Who Should Not Take Prozac

Prozac can be passed to babies during pregnancy and through breast milk. Consult with a doctor if you are pregnant or nursing before taking Prozac, to determine whether the benefits outweigh the risks.

There are also some potential risks for people aged 65 or older that should be discussed with a doctor. The safety and effectiveness of Prozac for use with children younger than 18 years of age has also not been established. 


The use of Prozac can carry risks, including the potential for clinical worsening and in rare cases, increased thoughts of suicide. Serotonin syndrome can also occur, particularly if used in conjunction with certain other medications. Close monitoring by your psychiatrist or doctor is important.

Prozac also comes with a black box warning that it may increase the risk of suicide in people younger than 25 years old. In these individuals, the drug may lead to suicidal thoughts or worsening of these types of thoughts. If you belong to this group, your prescribing doctor should monitor you, particularly in the early stages, for these serious issues.

Prozac may also activate mania in people who are prone.

If you are having suicidal thoughts, contact the National Suicide Prevention Lifeline at 1-800-273-8255 for support and assistance from a trained counselor. If you or a loved one are in immediate danger, call 911. 

For more mental health resources, see our National Helpline Database.


If you stop taking Prozac all of a sudden, you may notice withdrawal symptoms, including:

  • Dizziness
  • Confusion
  • Nightmares
  • Insomnia
  • Irritability
  • Crying spells

For this reason, never stop a medication without consulting a doctor. Prozac should always be tapered off to avoid withdrawal effects.

Alternatives to Prozac

If Prozac is not well tolerated, other SSRIs that are sometimes prescribed for anxiety include: 

Effexor XR (venlafaxine) is another antidepressant called a serotonin-norepinephrine reuptake inhibitor (SNRI) that also may be effective in treating anxiety.

Finally, benzodiazepines are another class of medication often used for anxiety, but they are generally a short-term solution because of their risk of dependence. Typical medications in this category include:


Prozac is an SSRI antidepressant that is sometimes used in the treatment of anxiety. It is often most effective when combined with psychotherapy. You should discuss your options with a doctor to determine if taking Prozac is the best approach to treat your symptoms. Potential side effects can occur and the medication may increase the risk of suicide in people age 25 and younger.

A Word From Verywell

If you've been prescribed Prozac for anxiety, you may feel worried about side effects and whether the medication will be helpful. Share your concerns with your prescribing doctor and stay in contact about how you are doing once you begin the medication. Communication is key to ensuring that this medication is used in an appropriate way for maximum effectiveness.

Frequently Asked Questions

  • What does Prozac feel like when it starts working?

    As Prozac begins working, you may begin to notice changes in your energy levels, sleep patterns, and appetite. These initial changes usually begin in the first couple of weeks after starting your medication. However, it may take several weeks before you begin to experience the full benefits of the medication such as changes in your anxiety levels and improvements in mood.

  • Does Prozac give you energy?

    As Prozac begins to work, you may notice increases in your energy levels. In some cases, it may cause symptoms of mania in some people taking this medication. Symptoms of mania include high energy levels, racing thoughts, trouble sleeping, and irritability. You should talk to your doctor if you notice such symptoms while taking Prozac. 

  • How long does it take for Prozac to work for anxiety?

    As with other antidepressant medications, it may take time before you begin to notice improvements in your anxiety symptoms. You might notice decreased anxiety symptoms after a few weeks of taking your medication, but it will take several weeks to experience the full effects.

  • How long should you take Prozac for anxiety?

    In many cases, it is recommended to continue taking an antidepressant for at least six months to a year after symptoms disappear. If you stop taking your medciation too soon, it may lead to a relapse of symptoms. You should never stop taking your medication without talking to your doctor first. Your doctor will likely recommend gradually tapering your dose over a period of several weeks in order to reduce the risk of withdrawal symptoms.

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6 Sources
Verywell Mind uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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