Fluoxetine: Indications, Administration, Side Effects, Interactions, Pregnancy and Frequently Asked Questions

It is an antidepressant known as SSRI (selective serotonin reuptake inhibitor).

It is often used to treat depression and sometimes obsessive-compulsive disorder and bulimia.

Fluoxetine helps many people recover from depression and has fewer unwanted effects than older antidepressants.

Fluoxetine is available only by prescription. It comes in tablets and capsules.

Key facts

  • In general, fluoxetine takes 4 to 6 weeks to work.
  • Common side effects include feeling sick, headaches and trouble sleeping. They are usually mild and disappear after a couple of weeks.
  • Fluoxetine can affect the unborn baby. Tell your doctor right away if you are trying to get pregnant or become pregnant while taking it.
  • It can cause withdrawal symptoms. Do not stop taking it without consulting your doctor.


Adults can take fluoxetine for depression, obsessive-compulsive disorder, and bulimia.

Children 8 years of age and older can take fluoxetine for depression.

Check with your doctor before you start taking fluoxetine if you:


  • You have had an allergic reaction to fluoxetine or any other medication in the past.
  • You have a heart problem because fluoxetine can speed up or change your heart rate.
  • Suppose you have ever taken other medications for depression. Some infrequently used antidepressants may interact with fluoxetine and cause very high blood pressure, even when suspended for a few weeks.
  • They are trying to get pregnant, are already pregnant, or are breastfeeding: fluoxetine is generally not recommended during pregnancy or breastfeeding.
  • You have an eye problem called glaucoma because fluoxetine can increase the pressure in your eye.
  • If you have diabetes, fluoxetine can make it harder to keep your blood sugar level stable. Check your blood sugar level more often during the first few weeks of fluoxetine treatment and adjust your diabetes treatment if necessary.


Take fluoxetine once a day. It does not alter the stomach so that you can take it with or without food.

You can take fluoxetine at any time, as long as it is kept at the same time every day. If you have trouble sleeping, it is best to take it in the morning.

The usual dose of fluoxetine is 20 mg per day in adults. However, you can start with a lower amount that gradually increases to a maximum dose of 60 mg per day.

Some people may need to take a lower dose of fluoxetine or take it less often. This includes people with liver problems and older adults.

The usual dose of fluoxetine in children is 10 mg per day, but it can be increased to 20 mg per day.

Missed dose

If you forget to take a dose every once in a while, do not worry. Take your following amount the next day at the usual time. Never take two doses simultaneously to make up for one forgotten.

If you miss doses frequently, it may be helpful to set the alarm to remind you. You can also ask your pharmacist for advice on other ways to help you remember to take your medication.


Ask your doctor for advice immediately. An overdose can cause potentially severe symptoms, such as:

  • Vomiting
  • Shake.
  • Dream.
  • Agitation.
  • Heart problems.
  • Lung problems.
  • Convulsions

Side effects

Like all medications, fluoxetine can cause side effects in some people, but many people have no side effects. Some of the common side effects of fluoxetine will gradually improve as your body gets used to it.

Common side effects

These side effects occur in more than 1 in 100 people. Keep taking the medication, but tell your doctor or pharmacist if these side effects bother you or do not go away:

  • Feeling sick.
  • Headaches.
  • I am not able to sleep.
  • Diarrhea.
  • I am feeling tired or weak.

Serious side effects

It infrequently occurs (in less than 1 in 100 people), but some people can have serious side effects when taking fluoxetine.

Tell a doctor immediately if you have:

  • Headache, problems concentrating, memory problems, not thinking, weakness, convulsions, or losing balance; may be signs of low sodium levels.
  • Thoughts about hurting yourself or ending your life.
  • Pain or pressure in the chest or difficulty breathing.
  • Severe dizziness or fainting
  • Attacks, euphoria, excessive excitement or excitement, or a feeling of restlessness that means you can not sit or sit still.
  • Climb or lose weight without trying.
  • Changes in your periods include heavy bleeding, spotting, or bleeding between periods.
  • Painful erections that last more than 4 hours can happen even when you are not having sex.

Or, if you have any sign of abnormal bleeding, which includes:

  • Vomiting dark blood or vomit, coughing up blood, blood in urine, and black or red stools; may be signs of bleeding in the intestine.
  • Bleeding from the gums or bruises that appear without reason or that get larger.
  • Any bleeding that is very bad or that you can not stop.

Serious allergic reaction

It is possible to have a severe allergic reaction to fluoxetine in rare cases.

A severe allergic reaction is an emergency. Contact a doctor immediately if you think you or someone around you has a severe allergic reaction.

The warning signs of a severe allergic reaction are:

  • Contract a skin rash that may include itching, redness, swelling, blistering, or peeling skin.
  • Wheezing
  • Oppression in the chest or throat.
  • Have trouble breathing or talking.
  • Swelling of the mouth, face, lips, tongue, or throat.

How to deal with side effects

You can reduce the chance of having a side effect if you take fluoxetine at night to sleep when the level of medication in your body is higher.

What to do with:

  • Feeling bad: try to take fluoxetine with or after food. It can also help to follow simple meals and avoid spicy food.
  • Not being able to sleep: take fluoxetine first thing in the morning.
  • Diarrhea: Drink plenty of water or other fluids. It can also help take oral rehydration solutions that you can buy at a pharmacy to prevent dehydration. Do not take other medications to treat diarrhea or vomiting without talking to a pharmacist or doctor.

Pregnancy and lactation

Fluoxetine is generally not recommended during pregnancy or breastfeeding.

No antidepressant is considered entirely safe to take in pregnancy or during breastfeeding. Your doctor will only want to prescribe fluoxetine when the benefits of taking the medication outweigh the risks.

Fluoxetine and similar antidepressants have been linked to a small risk of problems for the unborn baby when taken early or late pregnancy.

Fluoxetine is generally not recommended if you are breastfeeding. Fluoxetine passes into breast milk and has been linked to side effects in breastfed babies.

Tell your doctor if you are trying to get pregnant, if you are already pregnant, or if you are breastfeeding.


Some medications and fluoxetine can interfere with each other and increase the chances of you having side effects.

Tell your doctor if you are taking these medicines before starting fluoxetine:

  • Since fluoxetine can speed up or change the heartbeat, any medication that affects the heartbeat.
  • Any other medication for depression. Some infrequent antidepressants can interfere with fluoxetine and cause very high blood pressure, even when they have stopped for a few weeks.
  • Fluoxetine mixture with herbal remedies and supplements.

Do not take St. John’s wort for depression while being treated with fluoxetine, as it will increase the risk of side effects.

Tell your doctor or pharmacist if you take other medicines, including herbal remedies, vitamins, or supplements.

Frequent questions

How does fluoxetine work?

Fluoxetine is a group of antidepressants called selective serotonin reuptake inhibitors or SSRIs. It is believed that these medications work by increasing the levels of a chemical that improves mood called serotonin in the brain.

When will I feel better?

You may notice an improvement in your symptoms after 1 to 2 weeks, although it usually takes between 4 and 6 weeks before you feel the full benefits.

This is because it takes about a week for fluoxetine levels to accumulate in your body and then a few more weeks for your body to adapt and get used to it.

Do not stop taking fluoxetine after 1 to 2 weeks because you feel you are not helping your symptoms. Give the medication at least six weeks to work.

How will it make me feel?

Antidepressants like fluoxetine help give your mood a boost to feel better. You may notice that you sleep better and get along with people more easily because you are less anxious. You are expected to consider the little details that used to worry you.

Fluoxetine will not change your personality or make you feel euphorically happy. It will simply help you feel like yourself again.

However, do not expect to feel better overnight. Some people feel worse during the first weeks of treatment before they feel better.

How long will I take it?

Once you feel better, you will continue taking fluoxetine for several more months. Most doctors recommend that you take antidepressants for six months to a year after you no longer feel depressed. Stopping before then can make depression come back.

Is it safe to take it for a long time?

Fluoxetine is safe to take for a long time. There are no lasting harmful effects from taking it for many months and years.

However, taking fluoxetine for more than a year has been linked to a slight increase in the risk of developing diabetes.

What will happen if I stop taking fluoxetine?

If you stop taking fluoxetine suddenly, you may have unpleasant withdrawal symptoms. These include:

  • Dizziness.
  • Nausea.
  • Numbness or tingling in the hands or feet.
  • Problems with sleep.
  • Feeling agitated or anxious
  • Headaches.
  • Shake.

Withdrawal symptoms are usually harmless and disappear in a few days, but it is possible to prevent them by gradually reducing the dose when you stop taking this medication.

Do not stop taking fluoxetine unless your doctor tells you to.

Is it better than other antidepressants?

Fluoxetine is not better or worse than other antidepressants. However, sometimes people respond better to one antidepressant than to another. Talk to your doctor if you do not feel better after six weeks.

Will it affect my contraception?

Fluoxetine does not affect contraception, including contraceptive pills or the morning-after pill.

Will it affect my sex life?

The sound effects of fluoxetine can, after a while, improve your sex life as your mood increases and you become interested again in life and relationships.

Some of the possible adverse effects include:

  • Men can have painful erections, problems getting an erection and problems ejaculating.
  • Women may have some vaginal bleeding and may not reach orgasm in the same way as before.
  • You may have a low sex drive.

Sexual side effects should happen after the first few weeks. If they do not, and this causes a problem for you, go back to your doctor to see if there is another antidepressant you can try.

Will I gain weight or lose weight?

Fluoxetine may make you feel less hungry than usual, so you can lose weight when you start taking it.

If you start having problems with your weight while taking fluoxetine, talk to your doctor or pharmacist.

Can I drive or ride a bicycle?

Some people can not concentrate appropriately while taking fluoxetine. It would be best to stop driving and biking during the first days of treatment until you know how this medication makes you feel.

Can I drink alcohol?

You can drink alcohol while taking fluoxetine, but it can make you sleepy. It may be best to stop drinking alcohol during the first days of treatment until you see how the medication affects you.

Will recreational drugs affect you?

The induction effects of cannabis sleep can be added to fluoxetine, especially in people who have just started taking it. Cannabis and fluoxetine can also give you an accelerated heartbeat.

Methadone may increase the risk of side effects in people who take fluoxetine.

It can be potentially dangerous to take fluoxetine with:

  • Stimulants such as ecstasy or cocaine.
  • Hallucinogens like LSD.
  • New psychoactive substances such as ephedrine.

Fluoxetine has not been adequately tested with recreational drugs. Talk to your doctor if you think you might use recreational drugs while taking fluoxetine.

Is there any food or drink I should avoid?

You can eat and normally drink while taking fluoxetine.

Are there other treatments that will help?

Antidepressants, including fluoxetine, are just one of several approaches to treating depression. Other possible treatments include:

Choosing the most appropriate treatment for you depends on how long you have had depression, your symptoms if you have had previous episodes of depression, if the last treatment has worked, how likely you are to continue with your treatment, side effects, and preferences priorities.