Prozac (Fluoxetine): Uses, Side Effects, Dosage, & More

What Is Prozac (Fluoxetine)?

Prozac is an antidepressant medication frequently prescribed to address numerous mental health symptoms connected to depressive and anxious symptoms.^1,2,3 This medication for depression is a selective serotonin reuptake inhibitor (SSRI) approved for adults and children 8 and older.

Prozac is the brand name of fluoxetine, but people may encounter a combination product that includes fluoxetine and olanzapine (Zyprexa) called Symbyax.² Because it tends to be helpful while presenting mild side effects, Prozac is a good option as an initial antidepressant for someone to trial.

What Is Prozac Used For?

As an SSRI, Prozac is a versatile medication that can help treat symptoms connected to multiple mental health conditions.¹ With the drug’s ability to increase serotonin levels in the brain by blocking the reuptake of serotonin, it has a range of effects that include mood improvement and diminished anxiety.

A feature of Prozac is that the medication is effective whether the condition is in an acute or chronic phase. This means that people can safely use Prozac at different phases of their symptoms and still expect results.

Prozac is prescribed to treat the following conditions:^1,2,3

• Depression and depressive disorders including major depressive disorder (MDD) and bipolar depression
• Obsessive compulsive disorder(OCD)
• Bulimia nervosa, marked by a person binging food and using methods to purge
• Panic attacks and panic disorder with and without agoraphobia
• Symptoms of premenstrual syndrome (PMS) and premenstrual dysphoric disorder (PMDD), a condition that creates depression, tension, and irritability prior to menstruation

Off-Label (Non-FDA-Approved) Uses of Prozac

Because Prozac is beneficial for so many conditions, prescribers are always interested in expanding and furthering its uses. Through experimentation, research, and studies, medical and mental health professionals have found additional uses for Prozac.

Even though Prozac may not specifically be recommended for additional uses by the Food and Drug Administration in the U.S., people may receive off-label Prozac prescriptions.^2,3 Many medications are safely prescribed “off-label” and even if not FDA-indicated, using them in this manner is a common and accepted standard of care.

Off-label (non-FDA-approved) uses of Prozac include:

• Body dysmorphic disorder (BDD), a condition where the person is fixated on a body body they perceive to be a significant flaw
• Generalized anxiety disorder (GAD)
• Social phobia or social anxiety disorder
• Other specific phobias
• Post-traumatic stress disorder (PTSD)
• Disruptive mood dysregulation disorder (DMDD)
• Borderline personality disorder

Fluoxetine Warnings

Prozac is not an appropriate medication for everyone. Before a person considers taking Prozac, they should tell their doctor about any and all situations that may affect its use, including other prescriptions, allergies, and the possibility of pregnancy.²

Situations that may affect fluoxetine use include:

• Other prescriptions, especially other medications that interact with serotonin
• Vitamins and supplements (prescription and over-the-counter)
• If a person is pregnant or breastfeeding (Note: becoming depressed or anxious while pregnant is quite common)
• Allergies to other medications
• Previous suicidal thoughts, plans, or attempts

Perhaps the most significant warning about Prozac and other drugs from this class is the risk of suicidal thoughts and behaviors triggered by the medication.¹ Sometimes referred to the “Black Box Warning,” studies have found a connection between suicide and Prozac, especially in children, adolescents, and young adults.

There is not a good understanding regarding this increased suicide risk, but it does seem to shrink after the initial phase of treatment. As this issue has been studied further, Prozac seems to pose less risk to adolescents than do some of the other antidepressants. It is felt at this time, that the risks of suicide from the underlying condition (such as depression) outweigh the risks from taking the medication.

Always look for and attend to symptoms, including:¹

• Agitation and aggression
• Impulsivity
• Irritability and restlessness
• Hostility

These signs and symptoms could indicate an increased risk of suicidality. It is important to remember, however, that the risk is very low that someone starting Prozac will attempt or complete suicide.

What to Avoid While Taking Prozac

Many medications will interact with other substances in the body, and Prozac is no exception. New patients should always talk to their doctor about the foods, activities, and substances they should avoid while using Prozac. Mixing other medicines, substances, or alcohol with Prozac could either nullify or amplify its effects to dangerous levels.

Some people will have to avoid these things throughout their treatment with Prozac. Others will only need to limit or avoid them during the first days or weeks of their time taking Prozac.

Things to avoid while taking Prozac include:

• Alcohol and marijuana
• Other illegal drugs
• Driving and operating dangerous equipment, at least until the person finds out if the medication affects their judgment or reaction times
• Multiple medications or supplements that increase levels of serotonin in the brain to lower risk of serotonin syndrome, including the herbal supplement St. John’s Wort

How to Take Prozac

Everyone should always take their Prozac exactly as prescribed by their doctor. Any attempt to change dose, frequency, or route of administration is risky and should be avoided. Usually, fluoxetine is taken once a day with or without food. It’s an oral medication available as a tablet or capsule.² Like with other medications, it’s important to not chew or crush the medication before swallowing.

It should be noted that people need to use Prozac consistently before seeing results. Plan to take the medication for at least four weeks before noticing any of the desired effects.

Prozac Dosage

The dose of Prozac a person receives will depend on their prescriber’s assessment of the patient’s symptoms, health, risks, and supports. In many cases, the low dose of 10 mg or 20 mg is recommended to limit the risk of harmful side effects or allergic relationships.³

If there is reasonable evidence to suggest Prozac is well-tolerated, the prescriber can increase the daily dosage up to 80 mg. Not everyone benefits from the highest dose of Prozac. Some people may find the best results are somewhere in the middle.

What If You Miss a Dose?

Establishing a routine around medications is a helpful way to avoid missing a dose. Still, forgetting to take medication is a common experience.

If a person misses taking Prozac at their usual time, they should:³

• Take the regular dose if it is closer to their normal time
• Skip the regular dose if it is closer to the time of the next dose

In most cases, missing one dose of Prozac will not create issues. People that seem to be missing many doses should consider reminders or other treatment options.

Can You Overdose on Prozac?

Accidental overdoses of Prozac are rare, but people can intentionally take too much and put themselves in dangerous situations. An overdose of Prozac is a serious medical event. Due to this risk, prescribers often write the smallest quantity of Prozac available.¹

Someone who has overdosed on Prozac may exhibit these symptoms:²

• Being confused and unresponsive
• Unsteadiness
• Being nervous, shaky, and dizzy
• Abnormal heart rate
• Fever
• Fainting or loss of consciousness
• Seizure

Anyone who suspects an overdose of Prozac should seek emergency medical attention by calling 9-1-1 or going to an emergency department. There is no special treatment to reverse overdose symptoms, but the medical team can monitor vitals and ensure safety.

Additionally, someone prescribed Prozac should keep their medication in a secure location where the odds of accidental ingestion are unlikely.

Prozac Side Effects

Prozac has a long list of potential side effects, including nausea, headaches, and diarrhea. It is important to remember, though, that not everyone will notice these changes, and other people will decide the benefits of Prozac outweigh the problems.

The length of time it takes for Prozac to work and what Prozac feels like when it starts working varies on the individual. Some side effects will present soon after your first dose, while others may take more time to emerge. If side effects do appear, many of them will gradually disappear as your body adjusts to the medication.¹⁴

The ability to tolerate the side effects of Prozac will be an individual decision. People should always consider the risks of taking vs. not taking the medication.

Common Prozac side effects include:^2,4

• Feeling nauseous
• Headache
• Diarrhea
• Trouble falling asleep, trouble staying asleep, and strange dreams
• Feeling tired
• Feeling nervous or anxious
• Weight loss with loss of appetite
• Decreased sex drive or reduced sexual performance

Prozac side effects that need immediate attention include:^1,2,4

• Suicidality; some people on Prozac will report increase suicidal thought or actions.
• Serotonin syndrome, a serious condition marked by agitation, shakiness, vomiting, and hallucinations
• Allergic reaction, rash, and swelling of the face, hands, or feet
• Emergence of manic episodes
• Seizures
• Abnormal or unexpected bleeding

Rare fluoxetine side effects may include:¹

• Yawning
• Abnormal vision
• Excessive flatulence
• Fever

Fluoxetine Interactions

Anyone interested in Prozac should talk to their doctor about any possible interactions between the medication and other drugs. Prescribers need to know what medications people are taking and which ones they may be taking in the near future.

Prozac may interact with:¹

• Monoamine Oxidase Inhibitors (MAOIs)
• Drugs that interact with the central nervous system
• Drugs that increase levels of serotonin like other antidepressants or St. John’s-Wort
• Warfarin and NSAIDS like aspirin and ibuprofen
• Electroconvulsive therapy (ECT) due to risk of prolonged seizures

Prozac Withdrawal

The withdrawal effects of Prozac are still not well-understood, but someone who abruptly stops taking the medication may experience some unwanted effects. For this reason, a person should always take the medication as prescribed and speak to their doctor before ending treatment.²

When someone stops taking Prozac, they could note withdrawal symptoms like:²

• Mood changes
• Irritability and agitation
• Anxiety
• Dizziness
• Feeling tired but trouble sleeping
• Numbness or tingling in hand or feet
• Confusion
• Headaches

Prozac isn’t addictive or habit-forming in any way, so a person will not feel compelled or driven to take more of the medication. Symptoms will likely fade over time, and none appear to be of any danger. At times, the prescriber will shift the person to another medication while weaning them from Prozac to maintain treatment for depression. Contact the doctor or prescriber whenever questions about Prozac arise.

Questions to Ask Your Health Team About Prozac (Fluoxetine)

Prozac is a safe medication. Still, you should feel comfortable and confident before beginning your treatment, so ask your prescriber all the questions you have to make sure Prozac is right for you.

Questions to ask your care team about Prozac include:^2,5,6

1. What is Prozac? Why do you think it’s right for me?
2. What side effects should I expect, and how long do you think they will last?
3. What do SSRIs do in my body?
4. How long will I have to take these, and will I get addicted to them?
5. Other medications didn’t work for me, so what makes you think Prozac will help?
6. I’m planning to become pregnant; is Prozac still right for me or is another antidepressant recommended during pregnancy?
7. Is there a chance that this medication could make me feel worse instead of better?
8. If I’m having a bad day, should I take more Prozac?
9. Will Prozac take away my emotions or change my personality?
10. How does Prozac compare to Paxil as an antidepressant?

Your health team should take the time to answer each question to the best of their ability. Be sure to know who you can contact if you have additional questions in the future.

Final Thoughts On Prozac

As one of the most widely-used antidepressants for decades, Prozac is a good option for many people. That said, you should always be cautious of side effects and keep your prescriber informed of complications. If depression, anxiety, or other mental health issues have been a problem, talk to your doctor about Prozac.