Fluoxetine (Prozac) is a selective serotonin reuptake inhibitor (SSRI). It's used to treat several mental health conditions, including depression and panic disorder. The immediate-release pill and liquid are taken by mouth, typically once or twice daily. The delayed-release capsule is taken weekly, but it's approved only for depression. Some common side effects of fluoxetine (Prozac) include headaches, difficulty sleeping, and tiredness. Don't suddenly stop this medication if you've been taking it for a while; doing so can lead to symptoms of withdrawal.
Fluoxetine (Prozac) is a selective serotonin reuptake inhibitor (SSRI). It works mainly by raising the levels of serotonin, a chemical in your brain. Serotonin plays an important role in regulating your mood and emotions.
Source: DailyMed
Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.
Check with your doctor immediately if any of the following side effects occur:
Rare
cold sweats
confusion
convulsions (seizures)
cool pale skin
difficulty with concentration
drowsiness
dryness of the mouth
excessive hunger
fast or irregular heartbeat
headache
increased sweating
increased thirst
lack of energy
mood or behavior changes
overactive reflexes
purple or red spots on the skin
racing heartbeat
shakiness or unsteady walk
shivering or shaking
talking, feeling, and acting with excitement and activity you cannot control
trouble with breathing
unusual or incomplete body or facial movements
unusual tiredness or weakness
Incidence not known
Abdominal or stomach pain
agitation
back or leg pains
bleeding gums
blindness
blistering, peeling, or loosening of the skin
blood in the urine or stools
bloody, black or tarry stools
blue-yellow color blindness
blurred vision
chest pain or discomfort
clay-colored stools
continuing vomiting
dark urine
decreased urine output
decreased vision
difficulty with breathing
difficulty with swallowing
dizziness or lightheadedness
fainting
fast, pounding, or irregular heartbeat or pulse
general body swelling
high fever
hives, itching, puffiness or swelling of the eyelids or around the eyes, face, lips, or tongue
hostility
indigestion
irregular or slow heart rate
irritability
large, hive-like swelling on the face, eyelids, lips, tongue, throat, hands, legs, feet, or sex organs
light-colored stools
loss of appetite
loss of bladder control
muscle twitching
nightmares
no blood pressure or pulse
noisy breathing
nosebleeds
pain in the ankles or knees
painful, red lumps under the skin, mostly on the legs
pains in the stomach, side, or abdomen, possibly radiating to the back
pinpoint red spots on the skin
rapid weight gain
red or irritated eyes
red skin lesions, often with a purple center
redness, tenderness, itching, burning, or peeling of the skin
severe muscle stiffness
severe sleepiness
slurred speech
sores, ulcers, or white spots on the lips or in the mouth
stopping of heart
sudden shortness of breath or troubled breathing
sudden weakness in the arms or legs
sudden, severe chest pain
swelling of the face, ankles, or hands
swollen or painful glands
thoughts of killing oneself
tightness in the chest
tiredness
twitching, twisting, or uncontrolled repetitive movements of the tongue, lips, face, arms, or legs
unconsciousness
unpleasant breath odor
unusual bleeding or bruising
unusual drowsiness, dullness, tiredness, weakness, or feeling of sluggishness
unusually pale skin
use of extreme physical or emotional force
vomiting of blood
yellow eyes or skin
Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:
More common
Decreased appetite
Less common or rare
Abnormal dreams
breast enlargement or pain
change in sense of taste
changes in vision
feeling of warmth or heat
flushing or redness of the skin, especially on face and neck
increased appetite
increased sensitivity of the skin to sunlight
unusual secretion of milk, in females
yawning
Incidence not known
Cracks in the skin
loss of heat from the body
painful or prolonged erections of the penis
swelling of the breasts or breast soreness in both females and males
unusual milk production
Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.
Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.
Good choice for treating depression, OCD, and panic disorder
Less likely to make you sleepy compared to some other antidepressants, such as paroxetine (Paxil)
Taken by mouth, typically once daily (IR capsules and liquid) or once weekly (DR capsules, for depression only)
Can be taken with or without food
Can take up to 2 months for you to feel the full effects of the medication
Can raise the risk of suicidal thoughts and/or behavior in those age 24 or younger
Can interact with other medications, especially those affecting serotonin levels
Can cause withdrawal symptoms if you suddenly stop taking it
You can take fluoxetine (Prozac) with or without food, but fluoxetine (Prozac) also commonly causes nausea, especially when starting the medication and with dose changes; taking it with food might help with these side effects.
Don't change your dose or suddenly stop taking fluoxetine (Prozac) without talking to your provider first. Doing so can cause bothersome withdrawal symptoms like nausea, headache, and sleeping problems. Follow your psychiatrist's instructions to lower your dose slowly over a period of time to safely stop the medication.
Fluoxetine (Prozac) can cause some people to feel less hungry. Make sure you're eating a healthy and well-balanced diet while taking fluoxetine (Prozac) to ensure you're getting enough nutrition.
Although less likely than other SSRIs, fluoxetine (Prozac) can cause sexual side effects, such as ejaculation problems in males, low sex drive, and erectile dysfunction.
Fluoxetine (Prozac) can make you sleepy and dizzy. Don't drive or do anything requiring concentration until you know how this medication affects you.
Avoid drinking alcohol while taking fluoxetine (Prozac) because it can worsen some side effects (e.g., drowsiness, dizziness) as well as worsen your depression or anxiety symptoms.
Antidepressant medications, like fluoxetine (Prozac), can raise the risk of suicidal thoughts. Contact your psychiatrist right away if you or your loved ones notice any new or worsening changes in your behavior or mood while taking the medication.
Let your psychiatrist know if you're pregnant or thinking of becoming pregnant. They can talk with you about the benefits and risks of taking fluoxetine (Prozac) during pregnancy, as well as other treatment options. This is important because untreated mental health conditions during pregnancy can be harmful for you and your baby.
Fluoxetine (Prozac) can get into breastmilk and cause side effects (e.g., fussiness, sleepiness) in breastfed babies. Let your psychiatrist know if you're breastfeeding. They'll discuss the risks and benefits of continuing fluoxetine (Prozac).
Fluoxetine (Prozac) can cause some serious health issues. This risk may be even higher for certain groups. If this worries you, talk to your doctor or pharmacist about other options.
Risk factors: Age under 24 years old | History of depression or other mental health conditions
Taking fluoxetine (Prozac) can make your depression worse and cause you to have thoughts of suicide or harming yourself. The risk is highest if you're 24 years of age or younger, during the first few weeks of taking the medication, and when your dose changes. If you or anyone around you notice that you have suicidal thoughts or unusual behavior (e.g., anxiety, panic attacks, difficulty sleeping, feeling angry or irritated, restlessness) while taking fluoxetine (Prozac), get medical help right away.
Fluoxetine (Prozac) can cause anxiety and trouble sleeping in some people. If this side effect is very bothersome for you, talk with your psychiatrist.
Risk factors: Taking other medications that raise serotonin levels in your brain
Some people taking fluoxetine (Prozac) have developed a rare, but potentially life-threatening condition called serotonin syndrome. This condition happens where there's too much serotonin in the brain. Your risk for serotonin syndrome is higher if you use fluoxetine (Prozac) with other medications that can raise your serotonin levels, such as certain antidepressants, mental health medications, pain medications, and migraine medications. Let your psychiatrist know about all the medications you take before starting fluoxetine (Prozac). Also, don't start any new medications without talking to your psychiatrist first. Symptoms of serotonin syndrome include fast heart rate, sweating, muscle stiffness or spasms, fever, and confusion. Get medical help right away if you have any of these symptoms.
Severe allergic reactions to fluoxetine (Prozac) are possible, including life-threatening reactions like facial swelling, shock, and anaphylaxis (closing of the throat). If you notice hives, rash, red skin, swelling of the lips or tongue, or difficulty breathing after using fluoxetine (Prozac), get medical attention right away.
Fluoxetine (Prozac) can be taken for depression from bipolar disorder only if it's taken together with olanzapine (Zyprexa). This is because taking fluoxetine (Prozac) alone can trigger a bipolar manic episode. Before starting fluoxetine (Prozac), your psychiatrist will check to see if you have or are at risk for bipolar disorder. Talk to your psychiatrist right away if you or your loved ones notice unusual changes in your behavior, such as racing thoughts, restlessness, getting easily distracted, or unusual talkativeness.
Risk factors: Taking blood-thinners or other medications that raise your risk of bleeding
Fluoxetine (Prozac) can raise your risk of severe bleeding or bruising, especially if you're also taking antiplatelets (e.g., aspirin, clopidogrel (Plavix)) or anticoagulants (e.g., warfarin (Coumadin), apixaban (Eliquis), rivaroxaban (Xarelto)). Get medical help if you get bruising that doesn't improve, black-colored stools, pink or red-colored urine, coughing up or vomiting blood, or unusual bleeding from the nose or gums.
Risk factors: History of angle-closure glaucoma
Fluoxetine (Prozac) can lead to or worsen angle-closure glaucoma. You might need to see your optometrist regularly and get eye exams to check your eyes and make sure your vision isn't worsening. Contact your optometrist or psychiatrist if you notice changes in your vision after starting fluoxetine (Prozac).
Risk factors: Older adults | Taking diuretic medications
Fluoxetine (Prozac) can cause low blood sodium levels. Your provider might closely monitor your blood sodium levels before and during treatment with fluoxetine (Prozac). Get medical help right away if you experience weakness, confusion, difficulty concentrating, headache, or memory problems because these could be signs of low blood sodium levels, which is a medical emergency.
Risk factors: Low blood potassium or magnesium levels | Older age | Kidney problems | History of heart problems, slow heart rate, or other abnormal heart rhythms (arrhythmias) | Personal or family history of long QT syndrome | Taking other medications that cause QT prolongation
Fluoxetine (Prozac) can affect your heart rhythm, which can be serious and life-threatening. One example includes lengthening the time period from when the heart pumps and then relaxes. This is known as QT prolongation. Your risk is higher if you have certain factors, including abnormal electrolyte levels, heart rhythm problems, or are taking other medications that cause heart rhythm problems, such as amiodarone (Pacerone) and ciprofloxacin (Cipro), among others. To lower your risk, your psychiatrist or primary care provider might periodically monitor your heart and perform electrocardiograms (EKGs) to make sure your heart rhythm is normal. If you feel your chest pounding, have shortness of breath, have chest pain, or feel faint or lightheaded while taking fluoxetine (Prozac), call 911 right away.
In general, your psychiatrist will have you start with lower dose of fluoxetine (Prozac) and raise it slowly over a few weeks. If your total daily dose is higher than 20 mg, they might ask you to split the dose and take it twice daily.
Major depressive disorder (MDD)
Adults: The typical starting dose is 20 mg by mouth daily in the morning. The maximum recommended dose is 80 mg daily total.
Children ages 8 years and older: The typical dose ranges between 10 mg to 20 mg by mouth once daily.
Obsessive compulsive disorder (OCD)
Adults: The typical starting dose is 20 mg by mouth daily in the morning. The maximum recommended dose is 80 mg daily total.
Children ages 7 years and older: The typical starting dose ranges from 10 mg to 20 mg by mouth once daily, depending on body weight. The typical maintenance dose ranges from 20 mg to 60 mg daily.
Bulimia
Adults: The typical maintenance dose is 60 mg by mouth once daily in the morning.
Panic disorder
Adults: The typical starting dose is 10 mg by mouth once daily. The typical maintenance dose is 20 mg daily. The maximum recommended dose is 60 mg daily.
Depression from bipolar 1 disorder
Adults and children ages 10 years and older: The typical dose ranges from 20 mg to 50 mg by mouth daily, taken along with olanzapine (Zyprexa).
Treatment resistant depression
Adults: The typical dose ranges from 20 mg to 50 mg by mouth daily, taken along with olanzapine (Zyprexa).
Immediate-release fluoxetine also comes as tablet and liquid, but these only treat MDD, OCD, bulimia, and panic disorder.
Depression (ages 7 years and older): The typical dose is 90 mg by mouth once weekly. Your provider will let you know if and when you can transition to the fluoxetine (Prozac) DR capsule. Usually, you can start this medication a week after the last daily dose of fluoxetine (Prozac) 20 mg.
Using this medicine with any of the following medicines is not recommended. Your doctor may decide not to treat you with this medication or change some of the other medicines you take.
Using this medicine with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.
Using this medicine with any of the following medicines may cause an increased risk of certain side effects, but using both drugs may be the best treatment for you. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.
Currently take or have taken an MAOI, linezolid (Zyvox), or methylene blue (ProvayBlue) in the last 14 days
Taking pimozide
Taking thioridazine
By signing up, I agree to GoodRx's Terms and Privacy Policy, and to receive marketing messages from GoodRx.
American College of Obstetricians and Gynecologists. (202). Depression during pregnancy.
Aurobindo Pharma Limited. (2024). FLUOXETINE - fluoxetine hydrochloride capsule [package insert]. DailyMed.
Dr.Reddy's Laboratories Limited. (2021). FLUOXETINE HYDROCHLORIDE capsule, delayed release pellets [package insert]. DailyMed.
Lannett Company, Inc. (2023). FLUOXETINE- fluoxetine hydrochloride liquid [package insert]. DailyMed.
Marken, P. A., et al. (2000). Selecting a selective serotonin reuptake inhibitor: Clinically important distinguishing features. Primary Care Companion to the Journal of Clinical Psychiatry.
Powers, M., et al. (2015). Clinical Practice Review for GAD. Anxiety and Depression Association of America.
ScieGen Pharmaceuticals, Inc. (2023). FLUOXETINE- fluoxetine hydrochloride tablet [package insert]. DailyMed.
Wichniak, A., et al. (2017). Effects of Antidepressants on Sleep. Current Psychiatry Reports.
Zajecka, J., et al. (1999). Changes in adverse events reported by patients during 6 months of fluoxetine therapy. Journal of Clinical Psychiatry.
Research prescriptions and over-the-counter medications from A to Z, compare drug prices, and start saving.