Fluoxetine: Use, Side Effects, Dosage, Precautions


Fluoxetine is a prescription antidepressant that is also used to treat other mental health conditions in children and adults. This medication is taken by mouth and is available in generic (fluoxetine) and brand-name (Prozac, Sarafem, Prozac Weekly) forms.

Fluoxetine is a selective serotonin reuptake inhibitor (SSRI) that prolongs the action of the neurotransmitter serotonin. This drug can be very effective, but it is also associated with a number of serious side effects, such as suicidal ideation, heart rhythm disturbances, mania, serotonin syndrome, and more.

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Fluoxetine is prescribed to treat various mental health conditions. Typically, when this drug is prescribed, the treatment plan includes other treatments for diagnosed conditions, such as psychotherapy and lifestyle changes.

Fluoxetine is approved for the treatment of:

These conditions are associated with low serotonin levels or impaired serotonin metabolism. Serotonin is a neurotransmitter that affects mood, anxiety, and various functions. Normally, the serotonin transporter (SERT) removes serotonin from nerve endings to modulate the effects of serotonin. Fluoxetine supports serotonin activity by inhibiting the reuptake of this neurotransmitter SERT.2 The drug may also have other actions that influence its therapeutic effect.

Fluoxetine supports serotonin activity by inhibiting the reuptake of this neurotransmitter SERT .

A drug can also have other actions that affect its therapeutic effect.

Use not indicated on the label

Fluoxetine is sometimes used for conditions for which it is not approved by the FDA. These include various mood disorders, anxiety disorders, sexual disorders, and eating disorders.

Before drinking

Fluoxetine should be taken with caution and has several contraindications. If you are pregnant or breastfeeding, you and your doctor should consider the risks and benefits of taking this medicine. Also, fluoxetine is not considered safe for children younger than eight years old with depression or children younger than seven years old with OCD.

You should not take fluoxetine if one or the other SSRI has ever caused you an allergic reaction, such as a rash or trouble breathing.

Precautions and contraindications.

There are several conditions that can increase your risk of side effects from fluoxetine.

Conditions that may be associated with the side effects of fluoxetine include:

  • Serotonin syndrome : If you have had serotonin syndrome in the past in response to medication, it is important to know that fluoxetine can cause this condition. Symptoms of serotonin syndrome include agitation, confusion, diarrhea, and muscle stiffness.
  • Suicidal ideation : There is an increased risk of suicidal ideation associated with fluoxetine, especially in children, adolescents, and young adults.
  • Cardiac arrhythmias : Fluoxetine can cause irregular heart rhythms, and this is an especially high risk if you already have a predisposition to cardiac arrhythmias. This drug is especially associated with long QT syndrome .
  • Glaucoma : This drug can exacerbate some types of glaucoma, especially if your glaucoma is not treated.

Other SSRIs

Fluoxetine is a versatile drug. Prozac is the commonly prescribed brand of fluoxetine. Fluoxetine is available as a tablet, while Prozac is available as a tablet, extended-release tablet, and oral solution.

Other SSRIs include Zoloft (Sertraline) , Paxil (Paroxetine), Lexapro (Escitalopram) , Celexa (Citalopram), and others.


Prozac is available in a variety of doses and forms, including 10, 20, 40, and 60 mg tablets and oral solution. Manufacturer's recommended fluoxetine doses are listed below, although your healthcare provider may start with a lower dose and increase it to a different target dose, depending on your individual circumstances.

Starting doses and target doses recommended by the manufacturer for fluoxetine
Indication Dose
Depression in adults start with 20mg per day and stay on that target dose (can be increased to a maximum of 80mg per day)
Depression in children start with 10mg per day and can work up to 20mg per day
OCD in adults start with 20 mg per day and can increase to 60 mg per day
OCD in children start with 10 mg per day and can increase to 60 mg per day
Bulimia 60 mg daily in the morning
Panic disorder start with 10 mg per day with a target dose of 20 mg per day (maximum 60 mg per day)


If you have liver disease, your healthcare provider may prescribe a lower dose of fluoxetine than the recommended standard dose for your age and condition. A lower dose of fluoxetine is also recommended if you are an older person or have multiple medical conditions.

How to take and store

Fluoxetine tablets should be stored at 68 to 77 degrees Fahrenheit, away from light. It can be taken with or without food.

If you miss an appointment, take it as soon as you remember. But if it is almost time for your next dose, skip the missed dose and take the next one only at the scheduled time. Never take two doses at the same time.

Side effects

Fluoxetine is generally a safe drug, but it can cause side effects, some of which can be life-threatening or dangerous.


Be sure to call your doctor if you experience any side effects from fluoxetine. According to the manufacturer, the most common side effects of fluoxetine are:

  • Abnormal dreams or insomnia
  • Anorexia (decreased appetite or overeating) or nausea.
  • Nervousness or anxiety
  • Dry mouth
  • Rash
  • Tiredness or yawning
  • Perspiration
  • Shaking
  • General weakness
  • Diarrhea
  • Indigestion or heartburn
  • Flu, sinus, or sore throat syndrome
  • Abnormal ejaculation or impotence
  • Decreased libido
  • Low blood pressure

Severe form

Some of the side effects of fluoxetine are dangerous to your health. You should not stop taking your medicine abruptly if you experience serious side effects, but you should seek immediate medical attention.

Serious side effects of fluoxetine include :

  • Suicidal thoughts
  • Serotonin syndrome
  • Seizures
  • Mania
  • Bleeding
  • Angle closure glaucoma
  • Long QT syndrome
  • Hyponatremia
  • Severe weight loss

Warnings and interactions

It is best not to stop taking fluoxetine abruptly. You should talk to your doctor about a schedule to stop fluoxetine if you plan to stop taking it. After you stop taking fluoxetine, you may experience dizziness, balance problems, or mood disturbances.

Black box warning

Fluoxetine has a warning for suicidal behavior and suicidal thoughts in children, adolescents, and young adults. They should be monitored for the appearance or deterioration of suicidal thoughts and behaviors.

Drug interactions include:

  • Other serotonergic drugs : Fluoxetine can interfere with other drugs that interact with serotonin and their combination can increase the risk of serotonin syndrome.
  • Pimozide and thioridazine : Fluoxetine can increase the levels of pimozide and thioridazine. Also, if fluoxetine is taken with any of these medications, the combination may increase the risk of QT prolongation.
  • Haloperidol and clozapine : Fluoxetine can increase the levels of these antipsychotic drugs.
  • Phenytoin and carbamazepine : Fluoxetine can increase the levels of these anticonvulsants.
  • Monoamine oxidase inhibitors (MAOIs) : antidepressant MAOIs act differently from SSRIs. If you switch from an MAOI to fluoxetine, you need about two weeks between stopping the MAOI and starting fluoxetine, or up to six weeks when you stop taking fluoxetine and start the MAOI. Having both in your system can increase your risk of serotonin syndrome.
  • Tricyclic antidepressants (TCAs) : The levels of these antidepressants can be altered when taken together or when one starts within a few weeks of stopping the other.
  • Diazepam and Alprazolam : These anti-inflammatory drugs can interact with fluoxetine, potentially increasing levels and causing side effects.
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