Fluoxetine 20mg Capsules
WARNING: Drugs like this one have raised the chance of suicidal thoughts or actions in children and young adults. The risk may be greater in people who have had these thoughts or actions in the past. All people who take this drug need to be watched closely. Call the doctor right away if signs like depression, nervousness, restlessness, grouchiness, panic attacks, or changes in mood or actions are new or worse. Call the doctor right away if any thoughts or actions of suicide occur.This drug is not approved for use in all children. Talk with the doctor to be sure that this drug is right for your child. @ COMMON USES: It is used to treat depression.It is used to treat obsessive-compulsive problems.It is used to treat eating problems.It is used to treat panic attacks.It may be given to you for other reasons. Talk with the doctor.
Drug Class
Antidepressant
Pharmacologic Class
Selective Serotonin Reuptake Inhibitor (SSRI)
Pregnancy Category
Not available
FDA Approved
Dec 1987
DEA Schedule
Not Controlled
Overview
What is this medicine?
Fluoxetine is a medication used to treat depression, obsessive-compulsive disorder (OCD), panic disorder, bulimia nervosa, and premenstrual dysphoric disorder (PMDD). It works by helping to restore the balance of a natural substance (serotonin) in the brain, which can improve mood, sleep, appetite, and energy level.
How to Use This Medicine
Taking Your Medication
To use this medication correctly, follow your doctor's instructions and read all the information provided. Take your medication as directed, with or without food, and continue taking it even if you feel well. It's essential to adhere to your doctor's or healthcare provider's advice to ensure the best results.
Storing and Disposing of Your Medication
To maintain the quality and safety of your medication, store it at room temperature, protected from light, and in a dry place. Avoid storing it in a bathroom. Keep the lid tightly closed and store all medications in a secure location, out of the reach of children and pets.
Missing a Dose
If you miss a dose, take it as soon as you remember. However, if it's close to the time for your next scheduled dose, skip the missed dose and resume your regular dosing schedule. Do not take two doses at the same time or take extra doses to make up for the missed one.
To use this medication correctly, follow your doctor's instructions and read all the information provided. Take your medication as directed, with or without food, and continue taking it even if you feel well. It's essential to adhere to your doctor's or healthcare provider's advice to ensure the best results.
Storing and Disposing of Your Medication
To maintain the quality and safety of your medication, store it at room temperature, protected from light, and in a dry place. Avoid storing it in a bathroom. Keep the lid tightly closed and store all medications in a secure location, out of the reach of children and pets.
Missing a Dose
If you miss a dose, take it as soon as you remember. However, if it's close to the time for your next scheduled dose, skip the missed dose and resume your regular dosing schedule. Do not take two doses at the same time or take extra doses to make up for the missed one.
Lifestyle & Tips
- Take exactly as prescribed, usually once daily in the morning, with or without food.
- Do not stop taking fluoxetine suddenly, as this can cause withdrawal symptoms. Your doctor will guide you on how to slowly reduce the dose if needed.
- Avoid alcohol while taking fluoxetine, as it can worsen side effects like drowsiness or dizziness.
- Be cautious when driving or operating machinery until you know how fluoxetine affects you, as it may cause dizziness or drowsiness.
- Report any new or worsening symptoms, especially changes in mood, behavior, or thoughts of self-harm, to your doctor immediately.
- Inform your doctor and pharmacist about all other medications, supplements, and herbal products you are taking to avoid potential drug interactions.
Available Forms & Alternatives
Dosing & Administration
Adult Dosing
Standard Dose:
20 mg once daily in the morning
Dose Range:
10 - 80 mg
Condition-Specific Dosing:
Major Depressive Disorder:
Initial: 20 mg/day in the morning. May increase after several weeks to 40 mg/day. Max: 80 mg/day.
Obsessive-Compulsive Disorder (OCD):
Initial: 20 mg/day. May increase to 20-60 mg/day. Max: 80 mg/day.
Bulimia Nervosa:
60 mg/day in the morning.
Panic Disorder:
Initial: 10 mg/day. After 1 week, increase to 20 mg/day. Max: 60 mg/day.
Premenstrual Dysphoric Disorder (PMDD):
Continuous dosing: 20 mg/day. Intermittent dosing (luteal phase): 20 mg/day starting 14 days prior to menstruation through the first full day of menses.
Pediatric Dosing
Neonatal:
Not established
Infant:
Not established
Child:
Major Depressive Disorder (8-17 years): Initial 10-20 mg/day. OCD (7-17 years): Initial 10 mg/day, may increase to 20 mg/day after 2 weeks. Max 60 mg/day.
Adolescent:
Major Depressive Disorder (8-17 years): Initial 10-20 mg/day. OCD (7-17 years): Initial 10 mg/day, may increase to 20 mg/day after 2 weeks. Max 60 mg/day.
Dose Adjustments
Renal Impairment:
Mild:
No adjustment typically needed.
Moderate:
No adjustment typically needed.
Severe:
Use with caution; consider lower doses or less frequent dosing due to potential accumulation of fluoxetine and its active metabolite, norfluoxetine.
Dialysis:
Not well studied; use with caution. Fluoxetine is highly protein-bound and not effectively removed by dialysis.
Hepatic Impairment:
Mild:
Consider lower doses or less frequent dosing (e.g., 10 mg/day or 20 mg every other day).
Moderate:
Consider lower doses or less frequent dosing (e.g., 10 mg/day or 20 mg every other day).
Severe:
Consider lower doses or less frequent dosing (e.g., 10 mg/day or 20 mg every other day) due to prolonged half-life.
Pharmacology
Mechanism of Action
Fluoxetine is a selective serotonin reuptake inhibitor (SSRI). It potently and selectively inhibits the reuptake of serotonin (5-HT) into the presynaptic neuron, leading to an increased concentration of serotonin in the synaptic cleft and enhanced serotonergic neurotransmission. It has minimal affinity for other neurotransmitter receptors (e.g., alpha-adrenergic, histamine, muscarinic, dopamine, GABA).
Pharmacokinetics
Absorption:
Bioavailability:
Not precisely determined, but well absorbed.
Tmax:
6-8 hours (fluoxetine); 6-10 hours (norfluoxetine)
FoodEffect:
Food does not appear to affect the extent of absorption, but may delay Tmax slightly.
Distribution:
Vd:
20-45 L/kg (extensive distribution)
ProteinBinding:
Approximately 94% (primarily to albumin and alpha-1-glycoprotein)
CnssPenetration:
Yes (readily crosses the blood-brain barrier)
Elimination:
HalfLife:
Fluoxetine: 4-6 days; Norfluoxetine: 4-16 days (due to enterohepatic recirculation and slow elimination)
Clearance:
Not available (highly variable due to extensive metabolism and long half-life)
ExcretionRoute:
Renal (approximately 60% as metabolites), Fecal (approximately 15%)
Unchanged:
Less than 10% (fluoxetine and norfluoxetine combined)
Pharmacodynamics
OnsetOfAction:
Initial antidepressant effects may be seen within 1-2 weeks, but full therapeutic effects may take 4-6 weeks or longer.
PeakEffect:
4-6 weeks for full therapeutic effect.
DurationOfAction:
Due to long half-lives of fluoxetine and norfluoxetine, effects persist for several weeks after discontinuation.
Safety & Warnings
BLACK BOX WARNING
Antidepressants increased the risk compared to placebo of suicidal thinking and behavior (suicidality) in children, adolescents, and young adults in short-term studies of Major Depressive Disorder (MDD) and other psychiatric disorders. Anyone considering the use of fluoxetine or any other antidepressant in a child, adolescent, or young adult must balance this risk with the clinical need. Short-term studies did not show an increase in the risk of suicidality with antidepressants compared to placebo in adults beyond age 24; there was a reduction in risk with antidepressants compared to placebo in adults aged 65 and older. Depression and certain other psychiatric disorders are themselves associated with increases in the risk of suicide. Patients of all ages who are started on antidepressant therapy should be monitored appropriately and observed closely for clinical worsening, suicidality, or unusual changes in behavior. Families and caregivers should be advised of the need for close observation and communication with the prescriber.
Side Effects
Urgent Side Effects: Seek Medical Help Right Away
Although rare, some people may experience severe and potentially life-threatening side effects while taking this medication. If you notice any of the following symptoms, contact your doctor or seek medical attention immediately:
Signs of an allergic reaction, such as:
+ Rash or hives
+ Itching or red, swollen, blistered, or peeling skin (with or without fever)
+ Wheezing or tightness in the chest or throat
+ Trouble breathing, swallowing, or talking
+ Unusual hoarseness or swelling of the mouth, face, lips, tongue, or throat
Signs of low sodium levels, including:
+ Headache
+ Difficulty focusing or memory problems
+ Feeling confused or weak
+ Seizures or changes in balance
Sudden and significant weight gain or loss
Seizures
Dizziness
Slow heartbeat
Unexplained bruising or bleeding
Anxiety
Unusual thirst
Changes in menstrual period
Frequent urination
Trouble controlling body movements
Joint pain
Swollen glands
Painful erection (lasting more than 4 hours) or prolonged erection
Sex problems, such as:
+ Decreased interest in sex
+ Difficulty having an orgasm
+ Ejaculation problems
+ Trouble getting or keeping an erection
If you experience any of these symptoms, consult your doctor. They can help you manage these side effects and provide guidance on what to do next.
Serious but Rare Side Effects
In rare cases, this medication can cause a severe and potentially life-threatening condition called serotonin syndrome. The risk is higher if you take certain other medications. Seek medical help right away if you experience:
Agitation
Changes in balance
Confusion
Hallucinations
Fever
Fast or abnormal heartbeat
Flushing
Muscle twitching or stiffness
Seizures
Shivering or shaking
Excessive sweating
Severe diarrhea, stomach upset, or vomiting
Severe headache
Additionally, this medication can cause a type of abnormal heartbeat (prolonged QT interval), which can lead to another type of unsafe abnormal heartbeat (torsades de pointes). If you experience a fast or abnormal heartbeat, or if you pass out, seek medical help immediately.
Other Possible Side Effects
Like all medications, this drug can cause side effects in some people. While many individuals may not experience any side effects or only minor ones, it's essential to be aware of the possible effects. If you notice any of the following side effects, contact your doctor or seek medical attention if they bother you or do not go away:
Constipation
Diarrhea
Upset stomach
Vomiting
Decreased appetite
Dry mouth
Drowsiness
Strange or vivid dreams
Sleep disturbances
Fatigue or weakness
Flu-like symptoms
Yawning
Hot flashes
Feeling nervous or excitable
Shakiness
Excessive sweating
Headache
* Nose or throat irritation
This list is not exhaustive, and you may experience other side effects not mentioned here. If you have questions or concerns about side effects, consult your doctor. You can also report side effects to the FDA at 1-800-332-1088 or online at https://www.fda.gov/medwatch.
Although rare, some people may experience severe and potentially life-threatening side effects while taking this medication. If you notice any of the following symptoms, contact your doctor or seek medical attention immediately:
Signs of an allergic reaction, such as:
+ Rash or hives
+ Itching or red, swollen, blistered, or peeling skin (with or without fever)
+ Wheezing or tightness in the chest or throat
+ Trouble breathing, swallowing, or talking
+ Unusual hoarseness or swelling of the mouth, face, lips, tongue, or throat
Signs of low sodium levels, including:
+ Headache
+ Difficulty focusing or memory problems
+ Feeling confused or weak
+ Seizures or changes in balance
Sudden and significant weight gain or loss
Seizures
Dizziness
Slow heartbeat
Unexplained bruising or bleeding
Anxiety
Unusual thirst
Changes in menstrual period
Frequent urination
Trouble controlling body movements
Joint pain
Swollen glands
Painful erection (lasting more than 4 hours) or prolonged erection
Sex problems, such as:
+ Decreased interest in sex
+ Difficulty having an orgasm
+ Ejaculation problems
+ Trouble getting or keeping an erection
If you experience any of these symptoms, consult your doctor. They can help you manage these side effects and provide guidance on what to do next.
Serious but Rare Side Effects
In rare cases, this medication can cause a severe and potentially life-threatening condition called serotonin syndrome. The risk is higher if you take certain other medications. Seek medical help right away if you experience:
Agitation
Changes in balance
Confusion
Hallucinations
Fever
Fast or abnormal heartbeat
Flushing
Muscle twitching or stiffness
Seizures
Shivering or shaking
Excessive sweating
Severe diarrhea, stomach upset, or vomiting
Severe headache
Additionally, this medication can cause a type of abnormal heartbeat (prolonged QT interval), which can lead to another type of unsafe abnormal heartbeat (torsades de pointes). If you experience a fast or abnormal heartbeat, or if you pass out, seek medical help immediately.
Other Possible Side Effects
Like all medications, this drug can cause side effects in some people. While many individuals may not experience any side effects or only minor ones, it's essential to be aware of the possible effects. If you notice any of the following side effects, contact your doctor or seek medical attention if they bother you or do not go away:
Constipation
Diarrhea
Upset stomach
Vomiting
Decreased appetite
Dry mouth
Drowsiness
Strange or vivid dreams
Sleep disturbances
Fatigue or weakness
Flu-like symptoms
Yawning
Hot flashes
Feeling nervous or excitable
Shakiness
Excessive sweating
Headache
* Nose or throat irritation
This list is not exhaustive, and you may experience other side effects not mentioned here. If you have questions or concerns about side effects, consult your doctor. You can also report side effects to the FDA at 1-800-332-1088 or online at https://www.fda.gov/medwatch.
Seek Immediate Medical Attention If You Experience:
- Signs of Serotonin Syndrome: agitation, hallucinations, confusion, fast heartbeat, fever, sweating, shivering, muscle stiffness or twitching, loss of coordination, nausea, vomiting, diarrhea.
- New or worsening depression, anxiety, panic attacks, insomnia, irritability, hostility, aggressiveness, impulsivity, restlessness, or thoughts about suicide or self-harm.
- Unusual bleeding or bruising.
- Signs of an allergic reaction: rash, itching, swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.
- Seizures.
- Symptoms of low sodium (hyponatremia): headache, confusion, weakness, unsteadiness, memory problems.
Before Using This Medicine
Before Taking This Medication: Important Information to Share with Your Doctor
It is essential to inform your doctor about the following:
Any allergies you have, including allergies to this medication, its components, or other substances. Be sure to describe the allergic reaction you experienced, including any symptoms that occurred.
If you are currently taking or have recently taken certain medications, such as:
+ Linezolid
+ Methylene blue
+ Pimozide
+ Thioridazine
+ Medications for depression or Parkinson's disease, including isocarboxazid, phenelzine, tranylcypromine, selegiline, or rasagiline, within the last 14 days, as this may increase the risk of very high blood pressure
If you are taking any medications that can cause abnormal heart rhythms (prolonged QT interval). There are many medications that can cause this condition, so it is crucial to consult with your doctor or pharmacist if you are unsure.
To ensure your safety, it is vital to provide your doctor and pharmacist with a comprehensive list of:
All prescription and over-the-counter medications you are taking
Any natural products or vitamins you are using
Your medical history, including any health problems you have
This information will help your doctor determine whether it is safe for you to take this medication with your other medications and health conditions. Never start, stop, or change the dose of any medication without first consulting your doctor.
It is essential to inform your doctor about the following:
Any allergies you have, including allergies to this medication, its components, or other substances. Be sure to describe the allergic reaction you experienced, including any symptoms that occurred.
If you are currently taking or have recently taken certain medications, such as:
+ Linezolid
+ Methylene blue
+ Pimozide
+ Thioridazine
+ Medications for depression or Parkinson's disease, including isocarboxazid, phenelzine, tranylcypromine, selegiline, or rasagiline, within the last 14 days, as this may increase the risk of very high blood pressure
If you are taking any medications that can cause abnormal heart rhythms (prolonged QT interval). There are many medications that can cause this condition, so it is crucial to consult with your doctor or pharmacist if you are unsure.
To ensure your safety, it is vital to provide your doctor and pharmacist with a comprehensive list of:
All prescription and over-the-counter medications you are taking
Any natural products or vitamins you are using
Your medical history, including any health problems you have
This information will help your doctor determine whether it is safe for you to take this medication with your other medications and health conditions. Never start, stop, or change the dose of any medication without first consulting your doctor.
Precautions & Cautions
Important Warnings and Cautions
It is essential to inform all your healthcare providers, including doctors, nurses, pharmacists, and dentists, that you are taking this medication.
Caution with Daily Activities
Avoid driving and engaging in activities that require alertness until you understand how this medication affects you.
Stopping the Medication
Do not stop taking this medication abruptly without consulting your doctor, as this may increase the risk of side effects. If you need to discontinue the medication, your doctor will guide you on how to gradually stop taking it.
Interactions with Other Substances
Avoid consuming alcohol while taking this medication. Before using marijuana, other forms of cannabis, or prescription or over-the-counter (OTC) medications that may cause drowsiness, consult your doctor.
Monitoring Blood Sugar Levels
If you have diabetes (high blood sugar), closely monitor your blood sugar levels while taking this medication.
Delayed Effects
It may take several weeks to experience the full effects of this medication.
Bleeding Risks
This medication may increase the risk of bleeding, which can be life-threatening in some cases. Discuss this risk with your doctor.
Severe Reactions
Rarely, severe and potentially life-threatening reactions, including lung, kidney, or liver problems, have occurred with this medication. Seek immediate medical attention if you experience any of the following symptoms:
- Changes in urine output
- Dark urine
- Decreased appetite
- Upset stomach or stomach pain
- Light-colored stools
- Vomiting
- Yellow skin or eyes
- Shortness of breath
Eye Problems
Some individuals may be at a higher risk of developing eye problems while taking this medication. Your doctor may recommend an eye exam to assess this risk. If you experience eye pain, changes in vision, or swelling and redness around the eye, contact your doctor promptly.
Low Sodium Levels
This medication can cause low sodium levels, which can be life-threatening and lead to seizures, loss of consciousness, breathing difficulties, or death.
Effects on Growth in Children and Teens
In some cases, this medication may affect growth in children and adolescents. Regular growth checks may be necessary. Discuss this risk with your doctor.
Special Considerations for Older Adults
If you are 65 years or older, use this medication with caution, as you may be more susceptible to side effects.
Pregnancy and Breastfeeding
If you are pregnant, plan to become pregnant, or are breastfeeding, inform your doctor. Taking this medication in the third trimester of pregnancy may increase the risk of bleeding after delivery and pose health risks to the newborn. Your doctor will discuss the benefits and risks of taking this medication during pregnancy and breastfeeding.
It is essential to inform all your healthcare providers, including doctors, nurses, pharmacists, and dentists, that you are taking this medication.
Caution with Daily Activities
Avoid driving and engaging in activities that require alertness until you understand how this medication affects you.
Stopping the Medication
Do not stop taking this medication abruptly without consulting your doctor, as this may increase the risk of side effects. If you need to discontinue the medication, your doctor will guide you on how to gradually stop taking it.
Interactions with Other Substances
Avoid consuming alcohol while taking this medication. Before using marijuana, other forms of cannabis, or prescription or over-the-counter (OTC) medications that may cause drowsiness, consult your doctor.
Monitoring Blood Sugar Levels
If you have diabetes (high blood sugar), closely monitor your blood sugar levels while taking this medication.
Delayed Effects
It may take several weeks to experience the full effects of this medication.
Bleeding Risks
This medication may increase the risk of bleeding, which can be life-threatening in some cases. Discuss this risk with your doctor.
Severe Reactions
Rarely, severe and potentially life-threatening reactions, including lung, kidney, or liver problems, have occurred with this medication. Seek immediate medical attention if you experience any of the following symptoms:
- Changes in urine output
- Dark urine
- Decreased appetite
- Upset stomach or stomach pain
- Light-colored stools
- Vomiting
- Yellow skin or eyes
- Shortness of breath
Eye Problems
Some individuals may be at a higher risk of developing eye problems while taking this medication. Your doctor may recommend an eye exam to assess this risk. If you experience eye pain, changes in vision, or swelling and redness around the eye, contact your doctor promptly.
Low Sodium Levels
This medication can cause low sodium levels, which can be life-threatening and lead to seizures, loss of consciousness, breathing difficulties, or death.
Effects on Growth in Children and Teens
In some cases, this medication may affect growth in children and adolescents. Regular growth checks may be necessary. Discuss this risk with your doctor.
Special Considerations for Older Adults
If you are 65 years or older, use this medication with caution, as you may be more susceptible to side effects.
Pregnancy and Breastfeeding
If you are pregnant, plan to become pregnant, or are breastfeeding, inform your doctor. Taking this medication in the third trimester of pregnancy may increase the risk of bleeding after delivery and pose health risks to the newborn. Your doctor will discuss the benefits and risks of taking this medication during pregnancy and breastfeeding.
Overdose Information
Overdose Symptoms:
- Seizures
- Somnolence (extreme drowsiness)
- Nausea, vomiting
- Tachycardia (fast heart rate)
- Tremor
- Agitation
- Coma
- QT prolongation
- Ventricular arrhythmias
What to Do:
Seek immediate medical attention. Call 911 or Poison Control at 1-800-222-1222. Treatment is generally supportive, including maintaining an open airway, monitoring cardiac and vital signs, and managing symptoms.
Drug Interactions
Contraindicated Interactions
- Monoamine Oxidase Inhibitors (MAOIs) (e.g., phenelzine, tranylcypromine, selegiline, linezolid, methylene blue) - risk of serotonin syndrome. Allow at least 14 days between discontinuing MAOI and starting fluoxetine, and at least 5 weeks between discontinuing fluoxetine and starting MAOI.
- Thioridazine - risk of QT prolongation and ventricular arrhythmias (including Torsades de Pointes). Allow at least 5 weeks between discontinuing fluoxetine and starting thioridazine.
- Pimozide - risk of QT prolongation and ventricular arrhythmias.
Major Interactions
- Other serotonergic drugs (e.g., triptans, tricyclic antidepressants, fentanyl, lithium, tramadol, buspirone, St. John's Wort, other SSRIs/SNRIs) - increased risk of serotonin syndrome.
- Drugs that prolong the QT interval (e.g., Class IA and III antiarrhythmics, antipsychotics, macrolide antibiotics) - increased risk of arrhythmias.
- Drugs metabolized by CYP2D6 (e.g., tricyclic antidepressants, atomoxetine, risperidone, metoprolol, flecainide, propafenone) - fluoxetine is a potent CYP2D6 inhibitor, leading to increased plasma concentrations of these drugs.
- Warfarin and other anticoagulants/antiplatelets (e.g., NSAIDs, aspirin) - increased risk of bleeding due to fluoxetine's effect on platelet aggregation.
- Phenytoin - increased phenytoin levels and toxicity.
- Benzodiazepines (e.g., alprazolam, diazepam) - increased benzodiazepine levels.
Moderate Interactions
- Tricyclic Antidepressants (TCAs) - increased TCA levels and potential for toxicity.
- Lithium - potential for increased lithium levels and neurotoxicity.
- Carbamazepine - increased carbamazepine levels.
- Clozapine - increased clozapine levels and risk of adverse effects.
- Dextromethorphan - increased dextromethorphan levels and risk of serotonin syndrome.
- Metoprolol - increased metoprolol levels.
Minor Interactions
- Alcohol - generally advised to avoid due to potential for additive CNS depression, though no specific pharmacokinetic interaction.
Monitoring
Baseline Monitoring
Psychiatric evaluation (mood, anxiety, suicidal ideation)
Rationale: To establish baseline symptom severity and identify risk factors for suicidality.
Timing: Prior to initiation of therapy.
Complete Blood Count (CBC)
Rationale: To assess for any pre-existing hematologic abnormalities, though not routinely affected by fluoxetine.
Timing: Prior to initiation (optional, based on clinical judgment).
Liver function tests (LFTs)
Rationale: To assess baseline hepatic function, especially if hepatic impairment is suspected or dose adjustment is anticipated.
Timing: Prior to initiation (optional, based on clinical judgment).
Renal function tests (creatinine, BUN)
Rationale: To assess baseline renal function, especially if renal impairment is suspected.
Timing: Prior to initiation (optional, based on clinical judgment).
Electrolytes (Sodium)
Rationale: To establish baseline, especially in elderly or those at risk for hyponatremia.
Timing: Prior to initiation (optional, based on clinical judgment).
Routine Monitoring
Clinical response and symptom severity (e.g., HAM-D, MADRS, Y-BOCS)
Frequency: Weekly for first 4-6 weeks, then monthly or as clinically indicated.
Target: Reduction in symptom scores, improved mood/function.
Action Threshold: Lack of improvement after adequate trial, worsening symptoms.
Adverse effects (e.g., nausea, insomnia, sexual dysfunction, anxiety, agitation)
Frequency: Weekly for first 4-6 weeks, then monthly or as clinically indicated.
Target: Tolerable side effect profile.
Action Threshold: Intolerable side effects, requiring dose adjustment or discontinuation.
Suicidal ideation and behavior (especially in children, adolescents, young adults)
Frequency: Weekly for first 4 weeks, then every 2 weeks for next 4 weeks, then at 12 weeks, and as clinically indicated.
Target: Absence of new or worsening suicidal thoughts/behaviors.
Action Threshold: Emergence or worsening of suicidality; requires immediate assessment and intervention.
Weight and Height (pediatric patients)
Frequency: Every 3-6 months.
Target: Normal growth trajectory.
Action Threshold: Significant growth deceleration or weight changes.
Serum Sodium
Frequency: Periodically, especially in elderly, volume-depleted, or those on diuretics.
Target: 135-145 mEq/L
Action Threshold: <135 mEq/L (hyponatremia); requires investigation and management.
Symptom Monitoring
- Serotonin Syndrome (agitation, hallucinations, delirium, tachycardia, labile blood pressure, hyperthermia, hyperreflexia, incoordination, nausea, vomiting, diarrhea)
- Neuroleptic Malignant Syndrome (NMS)-like reactions (fever, rigidity, mental status changes, autonomic instability)
- New or worsening anxiety, agitation, panic attacks, insomnia, irritability, hostility, impulsivity, akathisia, hypomania, mania
- Suicidal ideation or behavior
- Hyponatremia (headache, difficulty concentrating, memory impairment, confusion, weakness, unsteadiness, falls)
- Abnormal bleeding or bruising
- Seizures
- Allergic reactions (rash, hives, swelling)
Special Patient Groups
Pregnancy
Use during pregnancy should be carefully considered, balancing potential risks to the fetus with the benefits of treating maternal depression. Untreated depression carries risks for both mother and fetus.
Trimester-Specific Risks:
First Trimester:
Some studies suggest a possible, but small, increased risk of cardiovascular malformations, particularly septal defects, with first-trimester exposure. However, data are conflicting and not conclusive.
Second Trimester:
No specific risks identified beyond general antidepressant use.
Third Trimester:
Exposure late in the third trimester may lead to complications in the neonate requiring prolonged hospitalization, respiratory support, and tube feeding (Persistent Pulmonary Hypertension of the Newborn - PPHN, and neonatal withdrawal syndrome/poor neonatal adaptation syndrome). PPHN risk is estimated at 1 in 500 live births for SSRI-exposed infants vs. 1 in 1000 for unexposed.
Lactation
Fluoxetine and its active metabolite, norfluoxetine, are excreted into breast milk. While some infants may experience no adverse effects, others may experience irritability, poor feeding, drowsiness, or weight loss. Monitoring the infant for adverse effects is recommended.
Infant Risk:
L3 (Moderate Risk) - Monitor infant for drowsiness, poor feeding, weight loss, and irritability. Consider alternative agents with lower milk levels or shorter half-lives if possible, especially in preterm infants or those with underlying health issues.
Pediatric Use
Fluoxetine is FDA-approved for MDD in children 8 years and older and OCD in children 7 years and older. A Black Box Warning exists regarding increased risk of suicidal thoughts and behavior in children, adolescents, and young adults. Close monitoring for clinical worsening and suicidality is crucial. Monitor growth and weight.
Geriatric Use
Use with caution in elderly patients. They may be more sensitive to the effects of fluoxetine, particularly hyponatremia and CNS side effects (e.g., dizziness, falls). Lower starting doses and slower titration may be appropriate. The long half-life of fluoxetine and norfluoxetine can lead to accumulation.
Clinical Information
Clinical Pearls
- Fluoxetine has the longest half-life among commonly used SSRIs, which can be advantageous for patients who occasionally miss a dose, but also means a longer washout period is required before starting MAOIs or other serotonergic drugs.
- The long half-life of fluoxetine and its active metabolite, norfluoxetine, means that steady-state concentrations are not reached for several weeks, and adverse effects or drug interactions may not fully manifest until later in therapy.
- Fluoxetine is a potent inhibitor of CYP2D6, which can lead to significant drug interactions with medications metabolized by this enzyme.
- It is one of the few SSRIs approved for bulimia nervosa.
- Due to its activating properties, fluoxetine is often dosed in the morning to avoid insomnia. If sedation occurs, evening dosing may be considered, but this is less common.
Alternative Therapies
- Other Selective Serotonin Reuptake Inhibitors (SSRIs): Sertraline, Paroxetine, Citalopram, Escitalopram, Fluvoxamine
- Serotonin-Norepinephrine Reuptake Inhibitors (SNRIs): Venlafaxine, Duloxetine, Desvenlafaxine
- Atypical Antidepressants: Bupropion, Mirtazapine, Trazodone, Vilazodone, Vortioxetine
- Tricyclic Antidepressants (TCAs): Amitriptyline, Nortriptyline, Imipramine
- Monoamine Oxidase Inhibitors (MAOIs): Phenelzine, Tranylcypromine (reserved for refractory cases)
- Psychotherapy (e.g., Cognitive Behavioral Therapy - CBT)
Cost & Coverage
Average Cost:
$10 - $50 per 30 capsules (generic 20mg)
Generic Available:
Yes
Insurance Coverage:
Tier 1 (Generic) or Tier 2 (Preferred Brand)
General Drug Facts
If your symptoms or health issues persist or worsen, it is essential to contact your doctor promptly. To ensure safe use, never share your medication with others or take someone else's medication. This medication is accompanied by a Medication Guide, which provides crucial information for patients. Please read this guide carefully and review it again whenever you receive a refill of this medication. If you have any questions or concerns about this medication, consult your doctor, pharmacist, or other healthcare provider. In the event of a suspected overdose, immediately call your local poison control center or seek emergency medical attention. When reporting the incident, be prepared to provide details about the medication taken, the amount, and the time it occurred.