Prozac (Fluoxetine): Uses, Side Effects, Dosage

Published on: 22 May 2023
Clinically Reviewed by Reshawna Chapple, PhD, LCSW

Prozac, or Fluoxetine, is one of the most prescribed medications today for certain mental health conditions, like depression. It is important to note that while it can be an effective treatment for many people, it’s essential to understand what you’re signing up for before taking Prozac. 

Here, we’re looking at all aspects of this common drug — including what is Prozac, its pros & cons, side effects, Prozac uses, and dosage options — so you can make an informed decision about whether or not Prozac is right for you.

What is Prozac?

Prozac is an antidepressant drug in the selective serotonin reuptake inhibitors (SSRIs) class. SSRIs are used to treat depression and other mood disorders. Prozac has been approved for use in adults and children over 8 years old for treating major depressive disorder, OCD, bulimia nervosa, panic disorder, and PMDD.

How does Prozac work?

Prozac works by increasing serotonin levels in the brain. Serotonin is a crucial regulator of emotions and behavior. Low levels of serotonin were linked to depression in recent studies, while higher amounts can help reduce feelings of sadness or low energy. 

By inhibiting the reuptake of serotonin into neurons, Prozac allows more serotonin to remain active in the brain, helping to regulate emotional response and behavior better than when diminished quantities are present.

How does Prozac make you feel?

As with any medication, it’s essential to understand how Prozac may affect you before taking it. Prozac can result in the following emotional and physical changes:

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  • Changes in mood — It’s very common to experience an improved mood from Prozac. Many people report feeling happier and calmer after starting treatment. 
  • Improved energy level — Some people state that after starting Prozac, they feel more motivated to practice self-care, like working out, engaging in activities, and being social. 
  • Changes in appetite — Many people experience a change in appetite when taking Prozac (either an increase or decrease).   
  • Sexual side effects — One potential side effect of taking Prozac is decreased libido. While not everyone on Prozac experiences this, some notice a decrease in sexual desire while on the medication, which could affect relationships if not discussed openly between partners. Also, men may experience erectile dysfunction-related issues.

Prozac Uses

“Prozac is approved for major depressive disorder, obsessive-compulsive disorder, panic disorder, bulimia, and binge eating disorder. However, your psychiatrist can also use the medication as an off-label use for the clinical need, addressing the symptoms of generalized anxiety disorder, PTSD, and premenstrual symptoms.”

Talkspace psychiatrist Dr. Muhammad Munir

Prozac for anxiety disorders like panic disorder has also been approved. Prozac is also often used off-label for other mental health conditions, such as various anxiety disorders or bipolar depression. It may also be prescribed with other medications — like antipsychotics or lithium — when needed.

Major depressive disorder (MDD)

MDD causes a general depressed mood and loss of interest in activities, things, and people you once enjoyed. In severe cases, MDD can cause suicidal thoughts and/or behaviors. Through improved serotonin levels in the brain, Prozac may help stabilize and improve the often-crippling symptoms of major depressive disorder. 

Obsessive-compulsive disorder (OCD)

OCD causes you to have obsessions — disturbing, recurring, and unwanted thoughts — that lead to compulsions — repeated, unhelpful behaviors in an attempt to stop thought patterns. In adults and older children, Prozac can help control intrusive thoughts that lead to compulsive behavior. 

Panic disorder

Panic disorder is a common mental health condition that causes intense fear. The resulting physical and emotional symptoms can seriously impede life and relationships. Prozac keeps serotonin in the system, reducing symptoms of anxiety and the chances of a panic attack.  

Bulimia nervosa

It’s been studied that Prozac can also help with bulimia nervosa, an eating condition that causes binge eating followed by purging in an effort to avoid weight gain. In fact, the drug has been shown to significantly reduce the frequency of episodes in studies

Premenstrual dysphoric disorder (PMDD)

PMDD is more serious than “regular” PMS and can cause depression and irritability during the days leading up to and following menstruation. 

Off-label uses

When addressing the question of what is Prozac used for, it’s important to note that there are several off-label uses for a variety of conditions. Off-label use means using a drug in ways not approved by the Food and Drug Administration (FDA) but prescribed by your doctor. 

Some common off-label uses of Prozac include: 

Pros & Cons of Prozac

Pros of ProzacCons of Prozac
Can reduce symptoms associated with depression, such as low energy levels, difficulty concentrating or sleeping, loss of interest in activities previously enjoyed, and feelings of worthlessness or guiltCommon side effect is drowsiness, which might interfere with daily activities
Works by increasing the levels of serotonin in the brain, helping to regulate moodSide effects can include nausea, vomiting, headache, insomnia, dry mouth, decreased appetite, weight gain, sexual dysfunction, increased sweating, and restlessness
May also be prescribed for anxiety disorders like panic disorder or obsessive-compulsive disorder (OCD)Might cause changes in behavior like agitation or aggression 

Affects serotonin level, not dopamine, like some other antidepressantsThough rare, it may result in thoughts about suicide or self-harm — particularly in younger people

“The greatest advantage of Prozac is its long half life, so missing a dose does not cause any withdrawal symptoms as may happen with other SSRIs. It’s once-a-day dosing. Limitations limit higher dosing when needed to address certain symptoms.”

Talkspace psychiatrist Dr. Muhammad Munir

Side Effects of Prozac

Although Prozac is generally considered safe and effective, you always want to be aware of potential side effects before starting a course of treatment. 

Common side effects of Prozac include:

  • Nausea
  • Headache 
  • Dizziness 
  • Drowsiness 
  • Dry mouth 
  • Loss of appetite 
  • Weight gain/loss 
  • Difficulty sleeping/insomnia

In addition to potential physical side effects, psychological ones should be considered. This can include feelings of apathy towards activities once enjoyed and decreased overall motivation. These symptoms usually improve over time, but it’s essential to monitor emotional states closely during treatment and alert healthcare providers if any concerning signs arise during drug use.

More severe but rare side effects include an increased risk of suicidal thoughts/behavior, especially among young people aged 18 – 24. If any unusual changes occur while on Prozac, contact your healthcare provider immediately.

Prozac Dosage

Prozac is available in several forms: 

  • Capsules
  • Tablets
  • Liquid solution
  • Delayed-release capsules

The dosage of Prozac varies depending on the condition being treated and other factors such as age and weight. Most people start at 20 mg daily, but this can vary from 10mg to 80mg or more depending on individual needs. 

Your doctor will prescribe the right dosage to help treat your symptoms.

How to take Prozac

Prozac can be taken with or without food, but you should take it at approximately the same time each day for optimal results. 

Do not crush, chew, break apart, or dissolve in liquid before taking — doing so could cause too much of the drug to enter your body all at once and lead to serious side effects such as seizures and serotonin syndrome, a potentially life-threatening condition. 

If you’re using an oral solution instead of tablets, make sure you use a measuring spoon/cup provided by your pharmacist.

You should always take Prozac exactly as prescribed by your doctor and be cautious of any potential interactions that can occur by taking other medications.

Additional Considerations

Before starting Prozac, thoroughly discuss all risks and benefits with your healthcare provider. 

It would be best if you also tracked how often you take doses throughout the day since missing doses can increase the risk of adverse reactions like Prozac withdrawal. 

Lastly, ensure all necessary lab tests have been done before beginning therapy so baseline values can be compared against future results if needed later on down the line.


Prozac can interact with other medications, including over-the-counter drugs and supplements. Be sure to tell your doctor about everything you’re taking before starting Prozac. 

Some interactions may increase the risk of side effects or make Prozac less effective. Examples include:

  • Monoamine oxidase inhibitors (MAOIs): Taking an MAO inhibitor and Prozac together can cause a dangerous reaction that increases serotonin levels in the body, leading to serious health problems such as coma or death.
  • Tricyclic antidepressants: Combining tricyclic antidepressants and Prozac can also increase serotonin levels too much, leading to potential side effects like confusion, agitation, rapid heart rate, fever, sweating, shivering, or shaking chills.
  • Warfarin: Taking warfarin along with Prozac may reduce warfarin’s effectiveness in thinning blood and increasing clotting time; this could lead to an increased risk of bleeding complications.
  • Aspirin: Taking aspirin while on Prozac may increase the risk of stomach bleeding due to increased acid production in the stomach lining caused by both medications combined.
  • Nonsteroidal anti-inflammatory drugs (NSAIDs): NSAIDs like ibuprofen taken alongside Prozac may also increase stomach acid production, leading to gastrointestinal issues such as nausea or vomiting.

If you’re taking any medication while on Prozac, talk to your doctor first so they can provide proper medical advice. They can help you understand how each drug will affect your treatment plan and assess possible risks when mixing them.


Don’t take Prozac if you’ve been prescribed and are taking thioridazine or pimozide. In addition, you shouldn’t take this drug if you’ve used monoamine oxidase inhibitors (MAOIs) in the last 2 weeks. You must wait at least 5 weeks after stopping Prozac before you start any MAOIs. 

Pay close attention to any changes in mood when you start Prozac — especially in younger people; Prozac can cause thoughts of suicide when first taken.

Do not stop taking Prozac without consulting your doctor first. 

Prozac Alternatives

Prozac is often the first medication prescribed for treating some mental health conditions. However, there are a variety of other medications that may be used. Potential alternatives to Prozac might include: 

Celexa (citalopram)

Celexa is an antidepressant medication in the same class as Prozac and works similarly by increasing serotonin levels in the brain. It may have fewer side effects than Prozac but has similar results when treating depression and anxiety.

Zoloft (sertraline)

Zoloft is another SSRI medication, like Prozac and Celexa, but it might be more effective for people with obsessive-compulsive disorder or post-traumatic stress disorder. It also tends to have fewer side effects than other antidepressants. Curious how it compares to Prozac? Review the differences between Prozac vs. Zoloft.

Effexor (venlafaxine)

Effexor is a selective norepinephrine reuptake inhibitor (SNRI), which increases serotonin and norepinephrine levels in the brain. This makes it particularly useful for people who don’t respond well to SSRIs alone or those with more severe symptoms of depression or anxiety disorders such as panic attacks or social phobia.

Wellbutrin (bupropion)

Wellbutrin is an atypical antidepressant that works differently from most other antidepressants. It targets dopamine receptors rather than serotonin receptors. As a result, Wellburtin can help reduce symptoms of depression without causing many common side effects associated with traditional antidepressants, such as weight gain or sexual dysfunction.

Lexapro (escitalopram)

Lexapro is another SSRI similar to Prozac, but it tends to work faster due to its higher potency compared to other existing drugs in this class, making it ideal for people who need quick relief from symptoms.  

Online Prozac Prescription Through Talkspace Psychiatry

Are you looking for a way to manage a mental health condition through a prescription drug? With Talkspace’s online psychiatry services, it’s now possible to get Prozac online. Talkspace can be accessed from anywhere, making getting help more accessible than ever. 

If you’re struggling with depression or another mental health condition, Prozac might help. We offer a safe and secure way to get professional guidance from experienced, qualified mental health professionals who can provide support so you can get your life back on track. Don’t wait any longer — take control of your mental health today with Talkspace.


  1. Erritzoe D, Godlewska BR, Rizzo G, et al. Brain serotonin release is reduced in patients with depression: A [11C]CIMBI-36 positron emission tomography study with a D-amphetamine challenge. Biological Psychiatry. 2022. doi:10.1016/j.biopsych.2022.10.012. Accessed February 7, 2023. 
  2. Fluoxetine (Prozac). NAMI. Accessed February 7, 2023. 
  3. Fluoxetine in the treatment of bulimia nervosa. A multicenter, placebo-controlled, double-blind trial. Fluoxetine Bulimia Nervosa Collaborative Study Group. Archives of general psychiatry. Accessed February 7, 2023. 

Talkspace articles are written by experienced mental health-wellness contributors; they are grounded in scientific research and evidence-based practices. Articles are extensively reviewed by our team of clinical experts (therapists and psychiatrists of various specialties) to ensure content is accurate and on par with current industry standards.

Our goal at Talkspace is to provide the most up-to-date, valuable, and objective information on mental health-related topics in order to help readers make informed decisions.

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