Introduction
Fluoxetine is a selective serotonin reuptake inhibitor (SSRI) antidepressant. Fluoxetine inhibits the uptake of serotonin by a nerve cells (neurons) and helps people with depression, panic, anxiety, or obsessive-compulsive symptoms.
Fluoxetine is a prescription medicine used to treat major depressive disorder, bulimia nervosa (an eating disorder), obsessive-compulsive disorder, panic disorder, and premenstrual dysphoric disorder (PMDD).
Fluoxetine is sometimes used together with another medication called olanzapine (Zyprexa) to treat manic depression caused by bipolar disorder.
This combination is also used to treat depression after at least 2 other medications have been tried without successful treatment of symptoms.
If you also take olanzapine (Zyprexa), read the Zyprexa medication guide and all patient warnings and instructions provided with that medication.
Warnings
You should not use fluoxetine if you also take pimozide or thioridazine, or if you are being treated with methylene blue injection.
Do not use fluoxetine if you have used an MAO inhibitor in the past 14 days (such as isocarboxazid, rasagiline, selegiline, phenelzine, or transcypromine). Do not use fluoxetine with thioridazine, linezolid, pimozide, or methylene blue injection.
You must wait at least 14 days after stopping an MAO inhibitor before you take fluoxetine. You must wait 5 weeks after stopping fluoxetine before you can take thioridazine or an MAOI.
Some young people have thoughts about suicide when first taking an antidepressant. Stay alert to changes in your mood or symptoms.
Fluoxetine could impair judgment, thinking, or motor skills. Use caution when operating machinery.
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.
1. Dosing
The dose of this medicine will be different for different patients. Follow your doctor’s orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.
The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.
- For oral dosage forms (capsules, delayed-release capsules, pulvules, or solution):
- For bulimia nervosa:
- Adults—60 milligrams (mg) once a day in the morning.
- Children—Use and dose must be determined by your doctor.
- For depression:
- Adults—At first, 20 milligrams (mg) once a day in the morning. Your doctor may adjust your dose as needed. If you are taking more than 20 mg per day, you may take the capsule once a day in the morning or 2 times a day (eg, morning and noon). However, the dose is usually not more than 80 mg per day.
- Children 8 years of age and older—At first, 10 or 20 mg once a day in the morning. Your doctor may adjust your dose as needed.
- Children younger than 8 years of age—Use and dose must be determined by your doctor.
- For depression associated with bipolar disorder (combination with olanzapine):
- Adults—At first, 20 milligrams (mg) of fluoxetine and 5 mg of olanzapine once a day, taken in the evening. Your doctor may adjust your dose as needed. However, the dose is usually not more than 50 mg of fluoxetine and 12 mg of olanzapine per day.
- Children 10 years of age and older—At first, 20 milligrams (mg) of fluoxetine and 2.5 mg of olanzapine once a day, taken in the evening. Your doctor may adjust your dose as needed. However, the dose is usually not more than 50 mg of fluoxetine and 12 mg of olanzapine per day.
- Children younger than 10 years of age—Use and dose must be determined by your doctor.
- For treatment resistant depression (combination with olanzapine):
- Adults—At first, 20 milligrams (mg) of fluoxetine and 5 mg of olanzapine once a day, taken in the evening. Your doctor may adjust your dose as needed. However, the dose is usually not more than 50 mg of fluoxetine and 20 mg of olanzapine per day.
- Children—Use and dose must be determined by your doctor.
- For obsessive-compulsive disorder:
- Adults—At first, 20 milligrams (mg) once a day in the morning. Your doctor may adjust your dose as needed. However, the dose is usually not more than 80 mg per day.
- Children 7 years of age and older—At first, 10 mg once a day in the morning. Your doctor may adjust your dose as needed. However, the dose is usually not more than 60 mg per day.
- Children younger than 7 years of age—Use and dose must be determined by your doctor.
- For panic disorder:
- Adults—At first, 10 milligrams (mg) once a day in the morning. Your doctor may adjust your dose as needed. However, the dose is usually not more than 60 mg per day.
- Children—Use and dose must be determined by your doctor.
- For premenstrual dysphoric disorder:
- Adults—At first, 20 milligrams (mg) once a day in the morning. Your doctor may have you take 20 mg every day of your menstrual cycle or for only 15 days of your cycle. Your doctor may adjust your dose as needed. However, the dose is usually not more than 80 mg per day.
- Children—Use and dose must be determined by your doctor.
2. Before Using
In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For this medicine, the following should be considered:
1. Allergies
Tell your doctor if you have ever had any unusual or allergic reaction to this medicine or any other medicines. Also tell your health care professional if you have any other types of allergies, such as to foods, dyes, preservatives, or animals. For non-prescription products, read the label or package ingredients carefully.
2. Pediatric
Appropriate studies performed to date have not demonstrated pediatric-specific problems that would limit the usefulness of fluoxetine in children. However, safety and efficacy have not been established to treat depression in children younger than 8 years of age, to treat obsessive-compulsive disorder in children younger than 7 years of age, and to treat depression that is part of bipolar disorder in children younger than 10 years of age.
Appropriate studies have not been performed on the relationship of age to the effects of fluoxetine in children with bulimia nervosa, panic disorder, or treatment resistant depression. Safety and efficacy have not been established.
3. Geriatric
Appropriate studies performed to date have not demonstrated geriatric-specific problems that would limit the usefulness of fluoxetine in the elderly. However, elderly patients are more likely to have hyponatremia (low sodium in the blood) than younger adults, which may require caution and an adjustment in the dose for patients receiving fluoxetine.
4. Breastfeeding
Studies in women breastfeeding have demonstrated harmful infant effects. An alternative to this medication should be prescribed or you should stop breastfeeding while using this medicine.
5. Drug Interactions
Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking this medicine, it is especially important that your healthcare professional know if you are taking any of the medicines listed below.
The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.
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.
3. Administration
1. Available Dosage Forms and Strengths
Fluoxetine should be administered once a day, either in the morning or evening and started at 20 mg daily. Fluoxetine is only available in an oral formulation as an oral solution (20 mg/5 mL), tablet (10 mg, 20 mg, 60 mg), capsule (10 mg, 20 mg, 40 mg), and delayed-release capsule (90 mg).
Fluoxetine is also available in a fixed-dose combination with olanzapine (6 mg olanzapine with 25 mg fluoxetine).
Considering that the medication can be efficacious at doses of 5 mg and weighing in on the adverse effect profile, it is essential to note that the drug can be administered in a smaller dosage. For an individual with poorly tolerated adverse effects, the fluoxetine may be dosed in 10 mg tablets instead of 20 mg to help minimize any adverse effects. Generally, 20 mg to 40 mg daily dosing is required to be effective for most individuals.
It also comes in a delayed-release capsule formulation with a dosage of 90 mg per week. Evidence suggests that the efficacy of the delayed-release formulation (90 mg once weekly) is similar to that of individuals receiving fluoxetine 20 mg daily.
Compared to other SSRIs, fluoxetine is not associated with the emergence of abrupt withdrawal symptoms (eg, sleep disturbances, dysphoria, fever, nausea) seen with other antidepressants due to prolonged half-life.[13][14]
2. Adult Dosing
1. Major depressive disorder
The typical starting dose of fluoxetine for major depressive disorder (MDD) is 20 mg daily. The maximum recommended dose of fluoxetine for MDD is 80 mg daily.[15]
2. Obsessive-compulsive disorder
The starting dose of fluoxetine for obsessive-compulsive disorder (OCD) is 20 mg daily. The typical maintenance dose for OCD is 20 to 60 mg.
3. Bulimia nervosa
TheAmerican Psychiatric Association guidelines recommend cognitive-behavioral therapy as the primary treatment for adults with bulimia nervosa. If there is minimal or no response to psychotherapy alone within 6 weeks, prescribing 60 mg of fluoxetine daily is recommended.[4]
4. Panic disorder
The typical starting dose of fluoxetine for panic disorder is 10 mg daily. After 1 week, consider increasing the fluoxetine to 20 mg daily. The maximum recommended dose of fluoxetine for panic disorder is 60 mg daily.
3. Special Patient Populations
1. Hepatic impairment
In patients with liver cirrhosis, the clearance of fluoxetine and its active metabolite (norfluoxetine) decreases, thus increasing the elimination of half-lives of these substances. Therefore, a lower/less frequent dose of fluoxetine should be used in patients with cirrhosis. In addition, caution is warranted when using fluoxetine in patients with diseases or conditions that could affect its metabolism.
2. Renal impairment
No dose adjustment of fluoxetine is required in patients with renal impairment. A study suggests that directly observed, once-weekly fluoxetine could be a feasible and well-tolerated treatment option for hemodialysis patients.[16]
3. Pregnancy considerations
Fluoxetine is categorized as Pregnancy Category C medicine. In the late third trimester, neonates exposed to SSRIs, including fluoxetine, have developed complications requiring prolonged hospitalization, tube feeding, and respiratory support. Complications of temperature instability, feeding difficulty, vomiting, respiratory distress, apnea, cyanosis, hypoglycemia, hypotonia, hypertonia, constant crying, hyperreflexia, tremor, jitteriness, irritability, and seizures are reported. These symptoms could precipitate right at delivery and are consistent with either a drug discontinuation syndrome or a direct toxic effect of SSRIs.The clinician may consider tapering fluoxetine in the third trimester.[17]
4. Breastfeeding considerations
As fluoxetine is excreted in human milk, nursing while on fluoxetine is not recommended.[17] If a woman used fluoxetine during pregnancy, most experts recommend against changing medications while breastfeeding. Otherwise, agents with lower excretion into breast milk may be preferred, especially while nursing a newborn or preterm infant. In addition, the breastfed infant should be monitored for behavioral adverse effects such as agitation, colic, irritability, poor feeding, and poor weight gain.[18]
5. Pediatric patients
Fluoxetine is FDA-approved for administration in pediatric patients with MDD and OCD. As with other SSRIs, decreased weight gain is associated with administering fluoxetine in children and adolescent patients. The dose for children with MDD and OCD is 10 mg once daily. According to the AACAP (American Academy of Child and Adolescent Psychiatry), it is recommended to offer selective serotonin reuptake inhibitor (SSRI) medication, particularly fluoxetine, to children and adolescents diagnosed with major depressive disorder. For those who respond positively to acute treatment with fluoxetine, AACAP suggests continuing with fluoxetine alone or combining it with cognitive-behavioral therapy to prevent the relapse or recurrence of major depressive disorder.[19]
Extensive metareview study results show that fluoxetine offers a strong risk-benefit ratio compared to other antidepressants in youth. This finding suggests that fluoxetine could be recommended as the initial treatment of choice for depressive disorders in children and adolescents.[20]
6. Older patients
Fluoxetine is effective for major depressive disorder in older patients.[21] The usual starting dose of fluoxetine is 10 mg once daily; it can be increased to 20 mg as tolerated.
4. Fluoxetine may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away.
- nervousness
- anxiety
- difficulty falling asleep or staying asleep
- nausea
- diarrhea
- dry mouth
- heartburn
- yawning
- weakness
- uncontrollable shaking of a part of the body
- loss of appetite
- weight loss
- unusual dreams
- stuffy nose
- sexual problems in males; decreased sex drive, inability to get or keep an erection, or delayed or absent ejaculation
- sexual problems in females; decreased sex drive, or delayed orgasm or unable to have an orgasm
- excessive sweating
- headache, confusion, weakness, difficulty concentrating, or memory problems
5. Some side effects can be serious. If you experience any of the following symptoms or those listed in the IMPORTANT WARNING or SPECIAL PRECAUTIONS section, call your doctor immediately.
- rash
- hives or blisters
- itching
- fever
- joint pain
- swelling of the face, throat, tongue, lips, eyes, hands, feet, ankles, or lower legs
- difficulty breathing or swallowing
- agitation, fever, sweating, confusion, fast or irregular heartbeat, shivering, severe muscle stiffness or twitching, hallucinations, loss of coordination, nausea, vomiting, or diarrhea
- fast, slow, or irregular heartbeat
- shortness of breath
- dizziness or fainting
- seizures
- abnormal bleeding or bruising
6. Human Experience
Worldwide exposure to fluoxetine hydrochloride is estimated to be over 38 million patients (circa 1999). Of the 1578 cases of overdose involving fluoxetine hydrochloride, alone or with other drugs, reported from this population, there were 195 deaths.
Among 633 adult patients who overdosed on fluoxetine hydrochloride alone, 34 resulted in a fatal outcome, 378 completely recovered, and 15 patients experienced sequelae after overdosage, including abnormal accommodation, abnormal gait, confusion, unresponsiveness, nervousness, pulmonary dysfunction, vertigo, tremor, elevated blood pressure, impotence, movement disorder, and hypomania.
The remaining 206 patients had an unknown outcome. The most common signs and symptoms associated with non-fatal overdosage were seizures,
somnolence, nausea, tachycardia, and vomiting.
The largest known ingestion of fluoxetine hydrochloride in adult patients was 8 grams in a patient who took fluoxetine alone and who subsequently recovered. However, in an adult patient who took fluoxetine alone, an ingestion as low as 520 mg has been associated with lethal outcome, but causality has not been established. Among pediatric patients (ages 3 months to 17 years), there were 156 cases of overdose involving fluoxetine alone or in combination with other drugs.
Six patients died, 127 patients completely recovered, 1 patient experienced renal failure, and 22 patients had an unknown outcome. One of the six fatalities was a 9-year-old boy who had a history of OCD, Tourette’s syndrome with tics, attention deficit disorder, and fetal alcohol syndrome. He had been receiving 100 mg of fluoxetine daily for 6 months in addition to clonidine, methylphenidate, and promethazine. Mixed-drug ingestion or other methods of suicide complicated all six overdoses in children that resulted in fatalities.
The largest ingestion in pediatric patients was 3 grams which was non-lethal. Other important adverse events reported with fluoxetine overdose (single and multiple drugs) include coma, delirium, ECG abnormalities (such as QT interval prolongation and ventricular tachycardia, including torsades de pointes-type arrhythmias), hypotension, mania, neuroleptic malignant syndrome-like events, pyrexia stupor, and syncope.
7. Animal Experience
Studies in animals do not provide precise or necessarily valid information about the treatment of human overdose. However, animal experiments can provide useful insights into possible treatment strategies. The oral median lethal dose in rats and mice was found to be 452 and 248 mg/kg, respectively. Acute high oral doses produced hyper-irritability and convulsions in several animal species. Among six dogs purposely overdosed with oral fluoxetine, five experienced grand mal seizures. Seizures stopped immediately upon the bolus intravenous administration of a standard veterinary dose of diazepam.
In this short-term study, the lowest plasma concentration at which a seizure occurred was only twice the maximum plasma concentration seen in humans taking 80 mg/day, chronically. In a separate single-dose study, the ECG of dogs given high doses did not reveal prolongation of the PR, QRS, or QT intervals. Tachycardia and an increase in blood pressure were observed.
Consequently, the value of the ECG in predicting cardiac toxicity is unknown. Nonetheless, the ECG should ordinarily be monitored in cases of human overdose.
Question
1. What is fluoxetine hydrochloride used for?
Fluoxetine is used to treat depression, obsessive-compulsive disorder (bothersome thoughts that won’t go away and the need to perform certain actions over and over), some eating disorders, and panic attacks (sudden, unexpected attacks of extreme fear and worry about these attacks)
2. What is the main side effect of fluoxetine?
Common side effects of taking fluoxetine (affecting up to one in ten people) include: not feeling hungry. weight loss. nervousness, anxiety, restlessness, poor concentration, feeling tense.
3. What is fluoxetine work by?
How does fluoxetine work? Fluoxetine is one of a group of antidepressants called selective serotonin reuptake inhibitors, or SSRIs. These medicines are thought to work by increasing the levels of serotonin in the brain. Serotonin is thought to have a good influence on mood, emotion and sleep.
4. What not to eat with fluoxetine?
Try taking fluoxetine with or after food. It may also help to stick to simple meals and avoid rich or spicy food. Make sure you rest and drink plenty of fluids. Try not to drink too much alcohol.
5. What organ does fluoxetine affect?
Fluoxetine (Prozac) is a type of depression medication. It belongs to a class of drugs called selective serotonin reuptake inhibitors (SSRIs). Doctors sometimes use Prozac to treat other conditions, such as anxiety. While not common, liver injury has been linked to Prozac use in some people.