Fluoxetine | Uses | Dosage | Side Effects | Precautions | Interactions | Drug Warnings
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Fluoxetine - Uses, Dosage, Side Effects, Precautions, Interactions, and Drug Warnings

Published on Nov 22, 2021 and last reviewed on Sep 14, 2022   -  5 min read


Fluoxetine is a prescription drug used to treat different types of depression, obsessive-compulsive disorder, some eating disorders, and panic attacks. Learn more about Fluoxetine, its uses, dosage, side effects, drug warnings, and precautions.

Fluoxetine - Uses, Dosage, Side Effects, Precautions, Interactions, and Drug Warnings


Fluoxetine is an oral prescription antidepressant drug that belongs to the group of selective serotonin reuptake inhibitors (SSRIs). It is used to treat the different types of depression, eating disorders, and panic attacks. It is also used to lessen premenstrual symptoms. People suffering from depression usually recover better after taking Fluoxetine, and it has minimal side effects than the other antidepressants.

Fluoxetine comes in four different forms:

  • Capsule.

  • Delayed-release tablets.

  • Delayed-release capsules.

  • Solutions.

Fluoxetine can also be used as a combination therapy. Fluoxetine is prescribed for adults, but it can also be given to children above the age of 8 years.

Drug Group:

Fluoxetine is an antidepressant. It belongs to the group of Selective Serotonin Reuptake Inhibitors (SSRIs). These are the drugs that are prescribed to ease the symptoms of moderate to severe types of depression. Other antidepressants belonging to this drug group are:

  • Citalopram (CELEXA).

  • Escitalopram (LEXAPRO).

  • Paroxetine (PAXIL, PEXEVA).

  • Sertraline (ZOLOFT).

These antidepressants are approved by the United States Food and Drug Administration (FDA).

What Is Fluoxetine Used For?

Fluoxetine is an oral prescription drug. It is used to treat the following conditions:

Fluoxetine is sometimes used along with other medications like Olanzapine to treat manic depression caused by bipolar disorder.

How Does Fluoxetine Work?

Fluoxetine is an antidepressant belonging to the group of Selective Serotonin Reuptake Inhibitors (SSRIs). These drugs are considered to work by increasing the levels of a chemical called Serotonin which helps to enhance the mood.

The Onset of Action:

The symptoms can improve after one to two weeks of taking Fluoxetine, but full benefits can be seen only after four to six weeks. Fluoxetine takes around a week to build up in the body and a few weeks longer to adapt and get used to it.

Try not to stop Fluoxetine after one week, just because there is no improvement in the symptoms as the medicine needs some time to work.

What Is the Dosage of Fluoxetine?

The dosage may differ according to the patient’s condition, the purpose for which it is prescribed, and general health. So it is recommended to take as per the doctors’ prescription.

Dosage of Fluoxetine

How to Use Fluoxetine?

Fluoxetine can be taken once daily with food because taking it without food can result in gastritis. Fluoxetine can be taken at any time of the day as long as it is the same time every day. In case if there is trouble sleeping when taken at night, then it can be taken during the daytime.

Missed Dose:

If you have missed a dose, then take the next dose on the next day at the usual time. Never try to take two doses to make up for the forgotten dose. If you keep forgetting to take the dose at the same time, then try to set a reminder so that you can fix it at the same time every day.

What If I Take Overdose?

When too much Fluoxetine is taken, there can be dangerous levels of the drug in the body. The symptoms of taking an overdose of Fluoxetine include the following:

  • Nausea.

  • Vomiting.

  • Dizziness.

  • Agitation.

  • Tremors.

  • Tiredness.

  • Fast heart rate.

What Are the Drug Warnings of Fluoxetine?

Fluoxetine is not generally recommended for people with the following conditions:

  • People who previously had an allergy after taking this drug.

  • People with blood clotting disorders.

  • For people with diabetes, it can lower blood sugar levels, which may later increase on stopping the drug.

  • People with bipolar disorder.

  • People with liver disease.

  • People with closed-angle glaucoma.

  • People with epilepsy or any other conditions that can cause seizures.

  • People with heart rhythm problems.

  • Pregnant women.

Is It Safe For Pregnant Women To Take Fluoxetine?

Fluoxetine is a category C drug, so it is generally not considered safe to be taken while being pregnant. Certain studies have shown that there can be adverse effects on the developing fetus when the mother takes Fluoxetine. So consult your doctor about taking this drug when you get pregnant.

Can Breastfeeding Women Take Fluoxetine?

Fluoxetine passes into breast milk usually in small amounts, but it may not harm the breastfed infant. So consult the doctor before taking this drug while breastfeeding.

What Are the Side Effects of Fluoxetine?

The common side effects of Fluoxetine are the following:

  • Decreased appetite.

  • Strange dreams.

  • Anxiety.

  • Nervousness.

  • Weakness.

  • Diarrhea.

  • Dry mouth.

  • Indigestion.

  • Decreased sexual drive.

  • Erectile dysfunction.

  • Difficulty sleeping.

  • Nausea.

  • Watery nasal discharge.

  • Sleepiness.

  • Sweating.

  • Hot flashes.

  • Tremors.

Fluoxetine can also cause some serious side effects, which include:

  • Serotonin syndrome - Some of the symptoms of serotonin syndrome are agitation, hallucinations, problems with coordination, increased heart rate, and overactive reflexes.

  • Mania - The symptoms of mania are finding it very hard to sleep, reckless behavior, racing thoughts, extreme happiness or irritability, and unusually grand ideas.

Is It Safe To Take Fluoxetine For A Long Time?

Fluoxetine is generally safe for most people when taken for an extended period of time. Still, few people may experience sexual side effects like not being able to get an erection or lower sexual drive. Otherwise, there are no lasting harmful side effects.

What Are the Interactions of Fluoxetine?

There are some medications that can interfere with the function of Fluoxetine when taken along. Either it can decrease the function of Fluoxetine, or it can increase the side effects. Some of the drugs that can interact with Fluoxetine are:

  • Benzodiazepines.

  • Warfarin.

  • Nonsteroidal anti-inflammatory drugs (NSAIDs).

  • Lithium.

  • Phenytoin.

  • Carbamazepine.

  • Other antidepressants.

  • Herbal supplements such as St.John’s wort can increase the side effects.

Drugs That Should Not Be Taken Along With Fluoxetine:

  • Monoamine oxidase inhibitors (MAOIs) such as:

  • Isocarboxazid.

  • Phenelzine.

  • Tranylcypromine.

  • Thioridazine.

What Are the Common Brand Names?

The common brand names of Fluoxetine are the following:

  • Prozac.

  • Sarafem.

  • Rapiflux.

  • Selfemra.

Frequently Asked Questions


What Is Fluoxetine?

Fluoxetine is a medicine used to treat depression, panic, anxiety, or obsessive-compulsive symptoms. It is a selective serotonin reuptake inhibitor (SSRI). They increase the availability of serotonin to be used by the brain to send signals.


When Should I Take Fluoxetine?

Fluoxetine is an antidepressant usually advised to be taken in the morning. This medicine can be taken with or without food. This medicine is supposed to be taken at the same time every day. It is available as a capsule, a tablet, a delayed-release capsule, and a solution to be taken by mouth.


What Are the Uses of Fluoxetine?

Fluoxetine is used for bipolar disorder, etc., to treat depression, obsessive-compulsive disorder, eating disorders, and panic attacks. They are also used to relieve symptoms of premenstrual dysphoric disorder (including mood swings, irritability, sore breasts, etc.).


What Are the Side Effects of Fluoxetine?

The side-effects of Fluoxetine include:
- Nervousness.
- Anxiety.
- Difficulty falling asleep or staying asleep.
- Nausea.
- Diarrhea.
- Dry mouth.
- Heartburn.
- Yawning.
- Weakness.
- Loss of appetite.
- Weight loss.
- Changes in sex drive
- Excessive sweating
- Headache, confusion, weakness, difficulty concentrating, or memory problems.


How Does Fluoxetine Work?

Serotonin helps maintain mental balance, and it is a feel-good hormone. SSRIs do not allow the reuptake of serotonin by the nerves and increase their availability in the brain. This helps carry the messages between the brain cells to regulate the body’s sleep-wake cycle.


What Drugs Should Be Avoided With Fluoxetine?

The following drugs are usually avoided with Fluoxetine-
- Pimozide, Thioridazine- antipsychotic medication.
- Monoamine oxidase inhibitor (MAO inhibitor)- monoamine oxidase removes the neurotransmitters like serotonin from the brain. An MAO inhibitor increases the availability of them in the brain.
- Methylene blue (treatment of methemoglobinemia in which hemoglobin level is decreased).
- Phenelzine (antidepressant).
- Selegiline (It is used in the treatment of Parkinson’s disease).
- Tranylcypromine (MAO inhibitor).


Does Fluoxetine Reduce Stress?

Fluoxetine is recommended to be an effective medicine against stress-related psychiatric disorders such as depression, OCD, etc. It can rapidly increase the availability of serotonin in the brain and help pass the message between the brain cells.


Will Fluoxetine Have Any Harmful Effects on the Brain?

Long-term use of Fluoxetine has been associated with adverse changes to the brain and improper brain development. Moreover, the long-term effects include treatment-resistant depression.


Does Fluoxetine Induce Sleep?

Fluoxetine may cause drowsiness or the ability to think clearly in some individuals. It induces poor muscle control, and hence activities such as driving using machines should be avoided.


What Are the Risks of Using Fluoxetine?

This medication is not supposed to be stopped suddenly. It is not considered to be safe during pregnancy. It can cause withdrawal symptoms. It also increases the risk for bleeding problems in diabetes.

Last reviewed at:
14 Sep 2022  -  5 min read




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