Prozac

Medically Reviewed by Harshi Dhingra, M.D.

Last Reviewed: Jun 24, 2022

Warnings

What are the risks of taking Prozac (fluoxetine)?

Prozac can cause serious health problems, especially in certain high-risk patients. Some of the risks of Prozac use include:

Suicidality: In a small number of people under the age of 24, mood elevators and antidepressant drugs like fluoxetine (Prozac) can increase the risk of suicidal thoughts and behaviors. The risk is highest when treatment is first started and after dose changes. Call the doctor without delay if you notice any unusual mood changes or behaviors.
Serotonin syndrome: This is a rare but potentially life-threatening condition in which there are dangerously high levels of serotonin in the brain. The risk of this occurring is higher in people who take other antidepressant drugs that can increase serotonin levels, lithium, triptans (cluster headache and migraines treatment), and St John’s Wort. The symptoms of serotonin syndrome include fever, confusion, muscle spasms, muscle stiffness, sweating, and a pounding heartbeat. Please seek immediate medical care if you experience these symptoms.
Increased bleeding risk: There can be an increased risk of bleeding in people who take Prozac along with drugs like blood thinners or NSAIDs (aspirin, Advil). Watch out for signs and symptoms like unexplained bruises, dark stools, pink or red urine, or unusual bleeding from the nose or gums. Call your doctor immediately if you notice any of these symptoms.
Abnormal heart rhythm: In people with a history of heart disease, Prozac can cause problems with the heart rhythm. This can also occur in people with low magnesium or low potassium levels. Contact your healthcare provider immediately or go to the nearest emergency room if you experience a fast heart rate, chest pain, difficulty breathing, or dizziness.
Low blood sodium levels: Prozac can cause low sodium levels in the blood. The risk is higher in people who are dehydrated and those who take diuretics (water pills). Call your doctor immediately if you experience confusion, headache, problems concentrating, memory difficulties, or weakness.
Mania: Some individuals with bipolar disorder (alternating depression and mania) seek medical attention for the first time during an episode of depression. Treating such people with an antidepressant such as Prozac can bring on a manic episode with abnormal excitement, euphoria, delusions, and overactivity. Call your doctor right away if you experience any unusual changes in behavior or mood.
Withdrawal symptoms: Stopping Prozac abruptly can lead to withdrawal symptoms such as agitation, anxiety, nausea, flu-like symptoms, dizziness, and sleep problems. These symptoms typically appear within 3 days of stopping the medication. Your doctor can help you safely come off Prozac by gradually reducing the dose.

If you are at a high risk of complications from Prozac use, your doctor or pharmacist can help you find other treatments for your condition.

What should I tell my doctor before starting Prozac (fluoxetine)?

Tell your doctor if you have ever had an allergic reaction to fluoxetine, any active or inactive ingredients in Prozac preparations, other SSRIs, or other medications. Your pharmacy can give you a list of ingredients.

Tell your healthcare provider about all your medical conditions. Prozac may not be suitable for people with certain medical conditions, including liver disease, heart disease, seizures, diabetes, glaucoma, or bleeding problems. Tell your doctor if you or anyone in your family has a history of suicide attempts or bipolar disorder. Tell your doctor if you or a family member has ever had a prolonged QT interval (a rare heart condition associated with irregular heartbeat, fainting, or sudden death). Also, tell your doctor if you have ever been told you have low potassium or magnesium.

Be sure to give your doctor a complete list of medications, including prescription drugs, over-the-counter medications, vitamins, dietary supplements, and herbal products, especially St. John’s Wort or tryptophan. This can help avoid serious drug interactions.

Tell your doctor if you are pregnant, could be pregnant, plan to get pregnant, or breastfeeding. Fluoxetine (Prozac) can cause problems in a newborn baby after delivery, especially if taken during the last few months of pregnancy.

What precautions should I take while on Prozac (fluoxetine)?

Keep all your healthcare appointments while on Prozac. Your doctor may want to see you often, especially at the start of treatment, to evaluate your response to the medication.

Watch out for any unusual mood or behavioral changes. A small number of people, especially those under the age of 24, can experience unexpected mental health changes and suicidality while on Prozac. Call your doctor immediately if you notice any emotional problems or unusual behaviors.

Prozac can make you drowsy. Do not drive, operate heavy machinery, or do anything that requires focus before knowing how this medicine affects you. Remember that alcohol can make drowsiness worse.

Tell your doctor if you become pregnant while on Prozac. This medicine should be used with caution in women who are pregnant or breastfeeding.

Prozac can cause closed-angle glaucoma (a condition associated with increased eye pressure). Your doctor may advise an eye examination before you start taking this medication. Call your doctor immediately if you have nausea, eye pain, vision changes, or redness and swelling around the eyes.

What are Prozac (fluoxetine) interactions?

Taking Prozac with some other medications can affect how the medication works. Drug interactions can also increase the risk of serious side effects. Your physician may choose a different antidepressant for you, change the dose or frequency of one or both medicines, and/or closely monitor you for side effects if there are known interactions between Prozac and your other medications.

Using Prozac with the following medications is not recommended:

pimozide (Orap)
thioridazine
Monoamine oxidase (MAO) inhibitors (Marplan, Zyvox, Nardil, Eldepryl, Parnate). Tell your doctor if you have stopped taking a monoamine oxidase inhibitor within the past 2 weeks - your doctor will advise against starting fluoxetine.
If you have recently stopped taking fluoxetine, you will need to wait at least 5 weeks before starting thioridazine or a monoamine oxidase inhibitor.

There can also be interactions between Prozac and medicines such as:

Benzodiazepines like alprazolam (Xanax)
Heart medications like Pacerone
Certain antibiotics like erythromycin, moxifloxacin, gatifloxacin, sparfloxacin
Aspirin and other nonsteroidal anti-inflammatory drugs (NSAIDs) (Advil, Motrin, Aleve, Naprosyn)
Amphetamines and dextroamphetamine (Adderall, Dexedrine, Dextrostat)
Anticoagulants or blood thinners (Coumadin, Jantoven)
Clopidogrel (Plavix)
Certain antidepressants (Elavil, Norpramin, Tofranil, Pamelor)
Buspirone
Certain medications for seizures (Tegretol, Dilantin, Phenytek)
Diazepam (Valium)
Digoxin (Lanexin)
Lithium
Diuretics or water pills
Dolasetron (Anzemet)
Pain medications like fentanyl (Duragesic) and tramadol (Ultram)
Flecainide (Tambocor)
Insulin or oral medications for diabetes
Certain anxiety medications
Certain medications for Parkinson's disease
Certain medications for mental illness (Clozaril, Versacloz, Inapsine, Haldol)
Medications for migraine headaches (Axert, Relpax, Frova, Amerge, Maxalt, Imitrex, Zomig)
pentamidine (Pentam)
quinidine (in Nuedexta)
Procainamide
Sedatives, tranquilizers, and sleeping pills
Other SSRIs (Celexa, Luvox)
Serotonin-norepinephrine reuptake inhibitors (SNRIs) (Pristiq, Cymbalta)
Vinblastine (Velban)

This list does not describe all possible Prozac interactions. Give your healthcare provider a complete list of your medications, including prescription and non-prescription drugs, vitamins and dietary supplements, and herbal products. Also, tell your health care provider if you smoke, drink alcohol, or use illegal drugs because some of these substances can cause serious health complications when used with prescription drugs.

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