Specifically, the Food and Drug Administration (FDA) has approved fluoxetine oral capsule for treating:
* For this use, fluoxetine is taken along with another drug called olanzapine.
This article describes possible side effects of fluoxetine oral capsule. You’ll also find information on cost savings and coupon options for fluoxetine. You can explore this overview article to learn more about fluoxetine oral capsule, including the drug’s uses, dosage, ways to save on cost, and more.
Fluoxetine oral capsule is a generic version of the brand-name drug Prozac. Fluoxetine also comes in other forms that you swallow, but these forms aren’t described in this article. To learn more about these forms, talk with your doctor.
Boxed warning: Risk of suicidal thoughts and behaviors in certain people
Fluoxetine has a boxed warning for the risk of suicidal thoughts and behaviors. This risk is higher in children, teenagers, and young adults. A boxed warning is the most serious warning from the FDA.
For details, see the “Side effects of fluoxetine in detail” section below.
More common side effects of fluoxetine
Fluoxetine oral capsule may cause mild or serious side effects. Below are some of the more common side effects of this medication.
Commonly reported side effects of fluoxetine oral capsule include:
- anxiety
- weakness
- nausea
- dry mouth
- widened blood vessels
Mild side effects of fluoxetine
Fluoxetine may cause certain mild side effects. Usually, mild side effects are temporary and can be easily managed. Tell your doctor or pharmacist if you have side effects that don’t go away or become bothersome.
Mild side effects of fluoxetine oral capsule that occurred in studies include:
- yawning
- widened blood vessels
- tremor
- sore throat
- runny nose
- sweating
- drowsiness
- unusual dreams
- appetite changes
- weakness
- anxiety
- dry mouth
- diarrhea
- upset stomach
- flu symptoms, such as chills and muscle aches
- trouble sleeping
- nausea
- nervousness
- rash
- mild allergic reaction*
* To learn more about this side effect, see the “Side effects of fluoxetine in detail” section below.
Fluoxetine oral capsule may cause more mild side effects than those listed above. For details, see the drug’s prescribing information.
Serious side effects of fluoxetine
Fluoxetine may cause certain serious side effects. If you have any serious side effects from fluoxetine oral capsule, call your doctor right away. But if you think you’re having a medical emergency or your side effects feel life threatening, take immediate action. Call 911 or a local emergency number, or go to the nearest emergency room.
After the Food and Drug Administration (FDA) approves a drug, it tracks and reviews side effects of the medication. Visit MedWatch’s website if you’d like to notify the FDA about a side effect you’ve had with fluoxetine oral capsule.
Serious side effects of fluoxetine oral capsule that occurred in studies include:
* To learn more about this side effect, see the “Side effects of fluoxetine in detail” section below.
† Fluoxetine oral capsule has a boxed warning for this side effect. A boxed warning is the most serious warning from the FDA. To learn more, see the “Side effects of fluoxetine in detail” section below.
Side effects of fluoxetine in children
For children, doctors prescribe fluoxetine oral capsule to treat the following conditions:
* For this use, fluoxetine is taken along with another drug called olanzapine.
Generally, side effects in children were similar to those in adults in studies of fluoxetine. The drugmaker also reported the following side effects in children:
If you’d like to know more about side effects in children taking fluoxetine oral capsule, talk with your doctor or pharmacist.
Side effects of fluoxetine in females vs. males
Sexual side effects were reported in studies of fluoxetine and other selective serotonin reuptake inhibitors (SSRIs) in the SSRI group. These side effects were reported in females and males.*
Side effects in females:
- lower sex drive
- delayed orgasm
- inability to orgasm
Side effects in males:
- lower sex drive
- priapism (erection that doesn’t go away)
- difficulty getting or keeping an erection
- difficulty with ejaculation
Talk with your doctor if you notice sexual side effects. They may suggest treatments or change your antidepressant medication.
* Sex and gender exist on spectrums. In this article, we use the terms “male” and “female” to refer to a person’s sex assigned at birth.
Common questions about side effects of fluoxetine
Here are answers to some common questions about side effects of fluoxetine oral capsule. If you have other questions, talk with your doctor or pharmacist.
Will fluoxetine 20 mg cause fewer side effects than the drug’s other strengths?
Fluoxetine 20 milligrams (mg) is expected to cause the same side effects as other strengths. That said, in general, the risk of side effects from a drug is lower with lower strengths compared with higher strengths.
Talk with your doctor if you’d like to know about side effects to watch for if you take a higher dose of fluoxetine.
Can fluoxetine cause you to gain weight?
Probably not. Studies of fluoxetine did not show weight gain. They rarely showed weight loss.
Weight loss from fluoxetine was more of a risk for people who were already underweight. It was also a risk for people with bulimia. (Keep in mind that the drug is used to treat this condition.)
Talk with your doctor if you notice changes in your weight when you take fluoxetine.
Does fluoxetine cause long-term side effects?
Yes, in some cases, fluoxetine oral capsule may cause long-term side effects. These can occur if you take the drug for a long time. They may also last for a while after you’ve stopped taking the drug.
Examples of long-term side effects reported with fluoxetine oral capsule include:
- heart rhythm changes
- appetite and weight changes
- glaucoma (high pressure inside your eye)
- bleeding problems
Talk with your doctor to learn more about these side effects and how to best manage them. Ask your doctor for more information about how long these side effects of fluoxetine may last.
Is withdrawal a possible side effect of fluoxetine?
Sometimes. With fluoxetine, withdrawal symptoms are usually called discontinuation symptoms. When you stop taking fluoxetine too quickly, you may have these side effects.
They can include:
- dizziness
- mood changes
- trouble sleeping
- hypomania (higher energy or impulsive mood)
- anxiety
- confusion
- headache
- a feeling of mild electric shocks in your body
If you’re stopping treatment with fluoxetine, your doctor may lower your dosage slowly over a period of time. This is called a taper. A fluoxetine taper decreases your risk of discontinuation symptoms.
If you have questions about stopping fluoxetine, talk with your doctor or pharmacist.
Coupon for fluoxetine
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Side effects of fluoxetine in detail
Below you’ll find details on some of the side effects of fluoxetine oral capsule.
Risk of suicidal thoughts and behaviors in certain people
In studies, suicidal thoughts and behaviors were a rare side effect in people taking fluoxetine oral capsule.
This side effect was more common in children, teenagers, and young adults. The risk was lower in people ages 24 years and older.
In addition, symptoms may include:
- behavior changes
- impulsive behavior
- aggression
- worsening depression
- restlessness
- hostility (feelings of unkindness or aggression)
Ways to manage
If you experience suicidal thoughts or behaviors, tell your doctor. They’ll likely recommend a change in dosage or a different medication. If you can’t talk with your doctor right away, talk with a friend or family member.
Suicide prevention
If you or someone you know is in crisis and considering suicide or self-harm, please seek support:
If you’re calling on behalf of someone else, stay with them until help arrives. You may remove weapons or substances that can cause harm if you can do so safely.
If you are not in the same household, stay on the phone with them until help arrives.
Sexual side effects
In studies, sexual side effects were rare in people taking fluoxetine oral capsule. But not everyone with this side effect tells their doctor. So it is not known how common these side effects are. Sexual side effects can be mild or serious.
With sexual side effects, you have a lower sex drive. Symptoms may also include difficulty with sexual performance or satisfaction.
This side effect was reported in males and females.* See the “Common questions about side effects of fluoxetine” section above for more details.
Certain factors can increase the risk of sexual side effects with fluoxetine oral capsule. These include mental or physical health conditions you already have. You may also be at higher risk of sexual side effects if you take certain other medications.
* Sex and gender exist on spectrums. In this article, we use the terms “male” and “female” to refer to a person’s sex assigned at birth.
Ways to manage
If you have concerns about sexual side effects, tell your doctor. They’ll likely look for possible causes other than fluoxetine. They may also suggest lifestyle changes or medications that can help.
Serotonin syndrome
In studies, serotonin syndrome was rare in people taking fluoxetine oral capsule. This side effect is usually serious. With serotonin syndrome, the level of the brain chemical serotonin in your body is too high.
Symptoms may include:
- muscle spasms
- dilated pupils (widening of the black center of the eye)
- flushing of skin (temporary warmth, redness, or deepening of skin color)
- fast heartbeat
- sweating
- loss of consciousness
- seizures
- coma
Certain factors can increase your risk of serotonin syndrome with fluoxetine oral capsule. These include taking other medications that also make serotonin levels higher. For example, triptan medications that are prescribed for migraine also have a risk of serotonin syndrome.
Ways to manage
If serotonin syndrome becomes severe, it can be life threatening. If you experience symptoms of serotonin syndrome, tell your doctor immediately. Or go to a medical facility for supportive care.
Allergic reaction
For some people, fluoxetine oral capsule can cause an allergic reaction.
But it’s not clear whether this side effect occurred in the drug’s studies.
Symptoms can be mild or serious, and they may include:
- itchiness
- skin rash
- swelling under the skin, usually affecting eyelids, lips, hands, or feet
- swelling of the mouth, tongue, or throat, which can make it hard to breathe
- flushing (temporary warmth, redness, or deepening of skin color)
Ways to manage
For mild allergic reaction symptoms, such as a mild rash, call your doctor right away. They may recommend treatments to help manage your symptoms. They’ll also let you know if you should keep taking the medication.
For severe allergic reaction symptoms, such as swelling or trouble breathing, call 911 or your local emergency number right away. These symptoms require immediate medical care because they can become life threatening. If you’ve had a serious allergic reaction to fluoxetine oral capsule, your doctor may recommend taking a different medication instead.
Warnings for fluoxetine
Below are some factors you may want to discuss with your doctor before taking fluoxetine oral capsule.
Boxed warning: Risk of suicidal thoughts and behaviors in certain people
Fluoxetine has a boxed warning for the risk of suicidal thoughts and behaviors in certain people. A boxed warning is the most serious warning from the Food and Drug Administration (FDA).
For details, see the “Side effects of fluoxetine in detail” section above.
Other warnings
It may not be safe for you to take fluoxetine oral capsule if you have specific health conditions. These are sometimes called drug-condition interactions. Other things may also affect whether fluoxetine oral capsule is a safe treatment option for you.
Before taking fluoxetine oral capsule, tell your doctor about your health and medications you take. Things to consider include:
Fluoxetine and pregnancy
It’s not known whether fluoxetine oral capsule should be taken during pregnancy. There are some reports of selective serotonin reuptake inhibitors (SSRIs) like fluoxetine taken during pregnancy. These reports show an increased risk of pregnancy loss or congenital abnormalities (also called birth defects).
These reports also showed similar risks if you stop taking SSRIs during pregnancy. For example, depression symptoms may become worse. (Keep in mind that the drug is used to treat depression and other mental health conditions.)
If you’re planning a pregnancy or can become pregnant, talk with your doctor before taking this medication. If you take this drug during pregnancy, your doctor may recommend that you join the pregnancy registry for fluoxetine. Pregnancy registries collect information to help doctors and patients understand the risks and benefits of taking medication during pregnancy.
Fluoxetine and breastfeeding
It’s not known whether fluoxetine oral capsule should be taken while breastfeeding. Studies show some side effects in infants exposed to fluoxetine through breastfeeding.
The side effects include:
- difficulty feeding
- difficulty gaining weight
- irritability
- agitation (restlessness or nervous excitement)
If you’re breastfeeding or planning to do so, talk with your doctor before taking this medication.
Fluoxetine and alcohol
Fluoxetine oral capsule is known to interact with alcohol.
Fluoxetine and alcohol can cause similar side effects. If you take them both, these side effects can be worse. Both fluoxetine and alcohol can cause:
- too much sweating
- sexual side effects
- nausea and vomiting
- low energy
- anxiety
- tremors
If you drink alcohol, talk with your doctor about whether it’s safe to consume it during your treatment with fluoxetine oral capsule.
What to ask your doctor
This article describes common and serious side effects of fluoxetine oral capsule. If your doctor prescribes this medication, they can discuss possible side effects with you. Let your doctor know if you have concerns or questions about treatment with this medication.
Here’s a list of some possible questions you may want to ask your doctor:
- Does my age affect my risk for suicidal thoughts or behaviors while I take fluoxetine?
- Do I have a high risk of sexual side effects from fluoxetine?
- Will a lower fluoxetine dosage cause fewer side effects?
- If I have side effects from fluoxetine, will they go away over time?
Disclaimer: Optum Perks has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.
