Fluoxetine

Fluoxetine is a prescription antidepressant used to treat major depressive disorder, obsessive-compulsive disorder (OCD), bulimia nervosa, and panic disorder. When used together with olanzapine (Zyprexa), it is also used to treat depressive episodes associated with bipolar I disorder and treatment-resistant depression.

Fluoxetine belongs to a class of antidepressants called selective serotonin reuptake inhibitors (SSRIs).

The original brand name of fluoxetine is Prozac, and it's now available as a generic.

Fluoxetine is FDA-approved to treat the following conditions:

• Major depressive disorder (MDD) for acute and maintenance treatment in adults and children aged 8 years and older
• Obsessive-compulsive disorder (OCD) for acute and maintenance treatment in adults and children aged 7 years and older
• Bulimia nervosa for acute and maintenance treatment of binge-eating and purging in adults with moderate to severe bulimia
• Panic disorder for the treatment of panic attacks in adults

When used in combination with olanzapine, fluoxetine is also FDA-approved for:

• Acute treatment of depressive episodes associated with Bipolar I disorder (depressive episodes) in adults and children aged 10 years and older
• Treatment-resistant depression for adults who have not responded to at least two adequate antidepressant trials

Fluoxetine alone is not approved for bipolar I depressive episodes or treatment-resistant depression - olanzapine must be used in combination for these indications.

Fluoxetine works by blocking the reabsorption (reuptake) of serotonin in the brain, leaving more of it active between nerve cells. Serotonin is a neurotransmitter that helps regulate mood, emotions, and sleep. By increasing the availability of serotonin, fluoxetine can relieve symptoms of depression, anxiety, and OCD.

Fluoxetine belongs to a class of antidepressants called selective serotonin reuptake inhibitors (SSRIs). SSRIs are one of the most commonly prescribed antidepressant classes because they are generally well-tolerated and effective across a range of conditions.

Most people need to take fluoxetine for 4 to 6 weeks before feeling the full effects.

Take fluoxetine exactly as prescribed by your doctor. Follow all directions on your prescription label and read all medication guides or instruction sheets. Your doctor may occasionally change your dose.

Swallow the delayed-release capsule whole and do not crush, chew, break, or open it.

Measure liquid medicine carefully. Use the dosing syringe provided, or use a medicine dose-measuring device (not a kitchen spoon).

It may take up to 4 weeks before your symptoms improve. Keep using the medication as directed and tell your doctor if your symptoms do not improve.

Tell your doctor if you have any changes in sexual function, such as loss of interest in sex, trouble having an orgasm, or (in men) problems with erections or ejaculation. Some sexual problems can be treated.

Do not stop using fluoxetine suddenly, or you could have unpleasant withdrawal symptoms. Ask your doctor how to safely stop using fluoxetine.

Store at room temperature away from moisture and heat.

Like all medications, Prozac carries some important warnings you should be aware of before and during treatment. Contact your doctor right away if you experience any of the following.

Boxed warning

Fluoxetine carries a boxed warning, the FDA's most serious warning, regarding suicidal thoughts and behavior. Antidepressants, including fluoxetine, may increase the risk of suicidal thoughts in children, adolescents, and young adults, particularly in the first few months of treatment or when your dose is changed. This risk was not seen in adults over 24, and adults 65 and older actually showed a reduced risk.

Anyone starting this medicine should be closely monitored for worsening mood or new or worsening suicidal thoughts, and families and caregivers should stay in regular contact with the prescriber.

Other warnings

• Serotonin syndrome: A potentially life-threatening condition that can occur when serotonin builds up to dangerous levels. This can occur when taken alone, but is more likely when taken with other serotonergic medications. Seek emergency care immediately if you experience agitation, hallucinations, rapid heartbeat, high fever, muscle rigidity, tremor, or seizures.
• Severe allergic reactions: Stop taking this medicine and seek emergency help if you develop trouble breathing, facial swelling, hives, or blistering rash.
• Abnormal bleeding: This medicine may increase the risk of bleeding or bruising, particularly if taken with blood thinners (such as warfarin), NSAIDs (such as ibuprofen or naproxen), or aspirin.
• Eye problems (angle-closure glaucoma): This medicine can cause angle-closure glaucoma with symptoms of eye pain, vision changes, or swelling around the eye in some people. An eye exam before starting treatment may be recommended for some people to assess their risk.
• Seizures: Tell your doctor if you have a history of seizures before starting this medicine, or have conditions that potentially increase your risk of seizures
• Manic episodes Fluoxetine may trigger mania, including racing thoughts, reckless behavior, drastically reduced need for sleep, and unusual bursts of energy or irritability.
• Changes in appetite or weight: Weight and appetite changes can occur, with some patients having significant weight loss. Children and adolescents should have their height and weight monitored regularly during treatment.
• Low sodium (hyponatremia): Low blood sodium levels can occur, particularly in older adults. Symptoms include headache, weakness, confusion, and difficulty concentrating.
• Heart rhythm changes (QT prolongation): Fluoxetine can affect the heart's electrical activity, potentially causing a serious and life-threatening irregular heartbeat. Seek medical attention if you experience a fast, slow, or irregular heartbeat, shortness of breath, or fainting.
• Sexual dysfunction: SSRIs, including fluoxetine, commonly affect sexual function. In men, this may include delayed or absent ejaculation or erectile problems. In women, it may include decreased libido or difficulty reaching orgasm. Talk to your doctor if this occurs, as treatment options are available.
• Drowsiness and impaired concentration: This medicine may affect your ability to think clearly, make decisions, or react quickly. Use caution when driving or operating machinery until you know how this medication affects you.
• Anxiety and Insomnia: May occur in some patients while taking this medicine.
• Blood sugar changes: People with diabetes may experience low blood sugar while taking this medicine, and high blood sugar when it is stopped. Your doctor may need to adjust your diabetes medications.

Tell your doctor about all your medical conditions and medications before starting fluoxetine (Prozac), as some may interact with it or affect whether it is safe for you.

Tell your doctor if you take any of the following medications or supplements:

• Triptans (for migraine)
• Antidepressants or mood stabilizers, including SSRIs, SNRIs, tricyclics, MAOIs, lithium, buspirone, or antipsychotics
• Amphetamines
• Opioid pain medications, including tramadol, fentanyl, meperidine, or methadone
• Over-the-counter supplements such as St. John's Wort or tryptophan
• Electroconvulsive therapy (ECT)

Many of these combinations can increase the risk of serotonin syndrome, a potentially serious condition.

Tell your doctor if you have or have had any of the following:

• Liver, kidney, or heart problems
• Seizures or epilepsy
• Bipolar disorder or mania
• Low sodium levels in the blood
• A stroke or high blood pressure
• Bleeding problems

Pregnancy

Tell your healthcare provider if you are pregnant, become pregnant, or plan to become pregnant while taking fluoxetine tablets. Using fluoxetine later in pregnancy may increase the risk of complications in the newborn, including problems that need a longer hospital stay, breathing support, or tube feeding, and a serious lung condition called persistent pulmonary hypertension of the newborn (PPHN). Untreated depression also carries risks in pregnancy, so discuss the benefits and risks of treatment with your healthcare provider rather than stopping on your own.

If you become pregnant while taking fluoxetine tablets, ask your healthcare provider about joining the National Pregnancy Registry for Antidepressants, which tracks pregnancy outcomes in women who take these medicines. You can enroll by calling 1-866-961-2388 or visiting womensmentalhealth.org.

Breastfeeding

Fluoxetine passes into breast milk. Tell your healthcare provider if you are breastfeeding or plan to breastfeed, and discuss the best way to feed your baby while you are taking fluoxetine tablets. If you do breastfeed, watch your baby for agitation, irritability, poor feeding, or poor weight gain, and seek medical advice if you notice any of these.

Do not take fluoxetine if any of the following apply to you. Tell your doctor or pharmacist about all medications you currently take or have recently stopped taking.

Do not take fluoxetine if you:

• Are allergic to fluoxetine or any of its ingredients
• Currently take a monoamine oxidase inhibitor (MAOI), including the antibiotic linezolid. If you are unsure whether your medication is an MAOI, ask your doctor or pharmacist
• Stopped taking an MAOI in the last 2 weeks
• Currently take pimozide (Orap) as this combination can cause a serious, potentially life-threatening irregular heart rhythm
• Currently taking thioridazine (Mellaril) as this combination can cause a dangerous irregular heart rhythm

Important timing rules with MAOIs and thioridazine:

• Wait at least 2 weeks after stopping an MAOI before starting fluoxetine
• Wait at least 5 weeks after stopping fluoxetine before starting an MAOI or thioridazine

Like all medications, Prozac can cause side effects. Not everyone experiences them, and many improve after the first few weeks as your body adjusts to the medication. Tell your doctor if any side effects bother you or do not go away.

Common Fluoxetine Side Effects

The most commonly reported side effects of fluoxetine (Prozac) include:

• Nausea
• Trouble sleeping (insomnia)
• Drowsiness or sleepiness
• Anxiety or feeling nervous or on edge
• Trembling or shaking (tremor)
• Excessive sweating
• Loss of appetite
• Diarrhea
• Dry mouth
• Indigestion or upset stomach
• Weakness or fatigue
• Sore throat
• Sinus congestion or infection
• Flu-like symptoms
• Skin rash
• Flushing or feeling of warmth
• Yawning
• Unusual or vivid dreams
• Decreased sex drive
• Difficulty getting or keeping an erection
• Delayed or abnormal ejaculation

Serious side effects

Get emergency medical help if you have signs of an allergic reaction to this medicine (hives, difficult breathing, swelling in your face or throat) or a severe skin reaction (fever, sore throat, burning eyes, skin pain, red or purple skin rash with blistering and peeling).

Report any new or worsening symptoms to your doctor, such as mood or behavior changes, anxiety, panic attacks, trouble sleeping, or if you feel impulsive, irritable, agitated, hostile, aggressive, restless, hyperactive (mentally or physically), more depressed, or have thoughts about suicide or hurting yourself.

This medicine may cause serious side effects. Call your doctor at once if you have:

• blurred vision, tunnel vision, eye pain or swelling, or seeing halos around lights;
• fast or pounding heartbeats, fluttering in your chest, shortness of breath, and sudden dizziness (like you might pass out);
• low levels of sodium in the body - headache, confusion, slurred speech, severe weakness, vomiting, loss of coordination, feeling unsteady; or
• severe nervous system reaction - very stiff (rigid) muscles, high fever, sweating, confusion, fast or uneven heartbeats, tremors, feeling like you might pass out.

Seek medical attention right away if you have symptoms of serotonin syndrome, such as: agitation, hallucinations, fever, sweating, shivering, fast heart rate, muscle stiffness, twitching, loss of coordination, nausea, vomiting, or diarrhea.

This is not a complete list of side effects, and others may occur. Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.

Fluoxetine (Prozac) is taken orally, and your doctor will determine the right dose for you based on your condition, age, and response to treatment. Always follow your doctor's instructions, do not change your dose or stop taking this medicine without speaking to them first.

Major Depressive Disorder (MDD)

Adults: Treatment typically starts at 20 mg once daily in the morning. Your doctor may increase the dose after several weeks if needed. The maximum dose is 80 mg/day.

Children and adolescents (aged 8 and older): Treatment starts at 10 mg or 20 mg per day. In lower-weight children, the starting dose and target dose may remain at 10 mg/day.

With all patients, the full effect of fluoxetine for depression may take 4 weeks or longer.

Obsessive Compulsive Disorder (OCD)

Adult dose: Treatment starts at 20 mg once daily in the morning and may be increased after several weeks if there is a lack of clinical improvement. The recommended dose range is 20 mg to 60 mg per day. Full therapeutic effect may take 5 weeks or longer.

Adolescents and higher-weight children (aged 7 and older): Treatment starts at 10 mg/day, increasing to 20 mg/day after 2 weeks. Additional dose increases may be considered after several more weeks if insufficient clinical improvement is observed. The recommended dose range is 20 mg to 60 mg per day.

Lower-weight children: Treatment starts at 10 mg/day with dose increases after several more weeks if there is a lack of clinical improvement. The recommended dose range of 20 mg to 30 mg per day, although experience with daily doses greater than 20 mg is very minimal,

Bulimia Nervosa

Adult dose: The recommended dose is 60 mg once daily in the morning. Your doctor may gradually increase your dose to this level over several days. Clinical trials showed that the 60 mg dose was effective in reducing binge-eating and purging behaviors.

Panic Disorder

Adult dose: Treatment starts at 10 mg/day, increasing to 20 mg/day after one week. Your doctor may adjust the dose after several weeks if needed. Clinical trials used a dose range of 10 mg/day to 60 mg/day, but the most commonly used dose in clinical trials was 20 mg/day.

General Dosing Notes

• Fluoxetine is usually taken in the morning to minimize the risk of sleep disturbances
• It may take several weeks to feel the full benefit of fluoxetine, do not stop taking it without talking to your doctor first
• Your doctor will periodically reassess whether you need to continue treatment
• Older adults may need a lower dose or may take fluoxetine less frequently than younger adults
• People with liver problems may also require a lower or less frequent dose
• If you have other medical conditions or take multiple medications, your doctor may need to adjust your fluoxetine dose accordingly

Take the medicine as soon as you can, but skip the missed dose if it is almost time for your next dose. Do not take two doses at one time.

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

Drinking alcohol can increase certain side effects of fluoxetine.

Avoid driving or hazardous activity until you know how fluoxetine will affect you. Your reactions could be impaired.

Using fluoxetine with other drugs that make you drowsy can worsen this effect. Ask your doctor before using opioid medication, a sleeping pill, a muscle relaxer, or medicine for anxiety or seizures.

Ask your doctor before taking a nonsteroidal anti-inflammatory drug (NSAID) such as aspirin, ibuprofen (Advil, Motrin), naproxen (Aleve), celecoxib (Celebrex), diclofenac, indomethacin, meloxicam, and others. Using an NSAID with fluoxetine may cause you to bruise or bleed easily.

Fluoxetine can cause a serious heart problem, and your risk may be higher if you also use certain other medicines for infections, asthma, heart problems, high blood pressure, depression, mental illness, cancer, malaria, or HIV.

Tell your doctor about all your current medicines. Many drugs can affect fluoxetine, especially:

• any other antidepressant;
• St. John's Wort;
• tryptophan (sometimes called L-tryptophan);
• a blood thinner - warfarin, Coumadin, Jantoven;
• medicine to treat anxiety, mood disorders, thought disorders, or mental illness - amitriptyline, buspirone, desipramine, lithium, nortriptyline, and many others;
• medicine to treat ADHD or narcolepsy - Adderall, Concerta, Ritalin, Vyvanse, Zenzedi, and others;
• migraine headache medicine - rizatriptan, sumatriptan, zolmitriptan, and others; or
• narcotic pain medicine - fentanyl, tramadol.

This list is not complete and many other drugs may affect fluoxetine. This includes prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible drug interactions are listed here.