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Fluoxetine

Brand Names: Prozac, Sarafem, Prozac Weekly, Selfemra

Generic Name: Fluoxetine

Drug Class: Antidepressants, SSRIs

What Is Fluoxetine and How Does It Work?

Fluoxetine is a prescription drug used to treat depression, panic attacks, obsessive-compulsive disorder, bulimia, and a severe form of premenstrual syndrome.

Fluoxetine may improve your mood, sleep, appetite, and energy level and may help restore your interest in daily living. It may also decrease fear, anxiety, unwanted thoughts, and the number of panic attacks. It may also reduce the urge to perform repeated tasks (compulsions such as hand-washing, counting, and checking) that interfere with daily living. Fluoxetine may lessen premenstrual symptoms such as irritability, increased appetite, and depression. It may decrease binging and purging behaviors in bulimia.

Fluoxetine is available under the following different brand names: Prozac, Sarafem, Prozac Weekly, and Selfemra.

Dosages of Fluoxetine:

Adult and pediatric dosages

Capsule

  • 10 mg
  • 20 mg
  • 40 mg

Tablets

  • 10 mg
  • 20 mg
  • 60 mg

Capsule, delayed-release: (adult dosage only)

  • 90 mg

Oral Solution

  • 20 mg/5ml

Dosage Considerations – Should be Given as Follows:

Adult dosage considerations:

Major Depressive Disorder

Prozac

  • 20 mg orally each day, may consider gradually increasing dose after several weeks by 20 mg/day; not to exceed 80 mg each day

Prozac Weekly

  • 90 mg orally each week

Children older than 8 years

  • 10-20 mg orally per day, initially start at 10 mg/day in lower weight children, may gradually increase dose after 1 week; not to exceed 20 mg per day

Obsessive-Compulsive Disorder

Adult

Prozac

  • 20 mg orally each day, may consider gradually increasing dose after several weeks by 20 mg/day (20-60 mg/day recommended range); not to exceed 80 mg each day

Prozac Weekly

  • 90 mg orally each week

Children older than 7 years

  • 10 mg orally per day, initially; may gradually increase dose after 2 weeks to 20 mg per day; further increases may be considered after several weeks

Adolescents and higher-weight children

  • Typical dosage range 20-60 mg per day

Lower-weight children

  • Typical dosage range 20-30 mg per day

Bulimia Nervosa

Initial or maintenance:

  • May adjust dose to 60 mg orally each day over several days

Panic Disorder

  • Initial: 10 mg orally each day for first week, THEN 20 mg orally each day. May consider gradually increasing dose after several weeks; not to exceed 60 mg per day; doses higher than 60 mg/day not evaluated

Premenstrual Dysphoric Disorder

  • Continuous (Sarafem): 20 mg orally each day initially; may gradually increase dose; not to exceed 80 mg/day, OR
  • Intermittent (Sarafem): 20 mg orally each day starting 14 days before menstruation and through first full day of menses (repeat each cycle)

Fibromyalgia (Off-label)

  • 20-80 mg orally each day

Dosing considerations

Migraine (Off-label)

Prophylaxis

  • 20-40 mg orally each day

Hot Flashes Caused by Hormonal Chemotherapy (Off-label)

  • 20 mg/day orally for 4 weeks

Raynaud Phenomenon (Off-label)

  • 20-60 mg/day orally

Dosing Modifications

Upon therapy discontinuation, taper gradually over 4-6 months to minimize incidence of withdrawal symptoms and allow for detection of re-emerging symptoms; if withdrawal symptoms intolerable, following a dose reduction, resume previously prescribed dose and/or decrease dose at more gradual rate.

Renal impairment: Use caution; drug accumulation may occur with severe renal impairment.

Hepatic impairment (cirrhosis): Decreased clearance of parent drug and active metabolite (norfluoxetine); lower or less frequent dose recommended.

Geriatric dosage considerations

  • Initial 10 mg orally per day, may gradually increase dose by 10-20 mg after several weeks as tolerated
  • Do not take at night unless sedation occurs
  • Preferred drug of choice in elderly over tricyclic antidepressants because of fewer side effects

What Are Side Effects Associated with Using Fluoxetine?

Common side effects include:

Rare side effects of Fluoxetine include:

Post marketing side effects of Fluoxetine reported include:

  • excessive or inappropriate production of milk

What Other Drugs Interact with Fluoxetine?

If your doctor has directed you to use this medication, your doctor or pharmacist may already be aware of any possible drug interactions and may be monitoring you for them. Do not start, stop, or change the dosage of any medicine before checking with your doctor, health care provider or pharmacist first.

Severe Interactions of Fluoxetine include:

Fluoxetine has serious interactions with at least 101 different drugs.

Fluoxetine has moderate interactions with at least 235 different drugs.

Fluoxetine has mild interactions with at least 43 different drugs.

This document does not contain all possible interactions. Therefore, before using this product, tell your doctor or pharmacist of all the products you use. Keep a list of all your medications with you, and share the list with your doctor and pharmacist. Check with your physician if you have health questions or concerns.

What Are Warnings and Precautions for Fluoxetine?

Warnings

  • In short-term studies, antidepressants increased the risk of suicidal thinking and behavior in children, adolescents, and young adults (under 24 years old) taking antidepressants for major depressive disorders and other psychiatric illnesses
  • This increase was not seen in patients over 24 years old, only a slight decrease in suicidal thinking was seen in adults over 65 years old
  • In children and young adults, the risks must be weighed against the benefits of taking antidepressants
  • Patients should be monitored closely for changes in behavior, clinical worsening, and suicidal tendencies; this should be done during the initial 1-2 months of therapy and dosage adjustments
  • The patient's family should communicate any abrupt changes in behavior to the health-care provider
  • Worsening behavior and suicidal tendencies that are not part of the presenting symptoms may require discontinuation of therapy
  • Not FDA approved for treatment of bipolar depression of children younger than 7 years
  • This medication contains fluoxetine
  • Do not take Prozac, Sarafem, Prozac Weekly, or Selfemra if you are allergic to fluoxetine or any ingredients contained in this drug
  • Keep out of reach of children
  • In case of overdose, get medical help or contact a Poison Control Center immediately

Contraindications

  • Hypersensitivity
  • Concomitant use with pimozide or thioridazine
  • Breastfeeding

Coadministration with monoamine oxidase inhibitors (MAOIs)

  • Coadministration may cause serotonin syndrome
  • Coadministration of monoamine oxidase inhibitors with fluoxetine or within 5 weeks of discontinuing fluoxetine
  • Initiating fluoxetine within 14 days of stopping a monoamine oxidase inhibitors
  • Starting fluoxetine in a patient who is being treated with linezolid or IV methylene blue is contraindicated because of an increased risk of serotonin syndrome
  • If linezolid or IV methylene blue must be administered, discontinue fluoxetine immediately and monitor for central nervous system toxicity; may resume fluoxetine 24 hours after last linezolid or methylene blue dose or after 5 weeks of monitoring, whichever comes first

Effects of Drug Abuse

  • None

Short-Term Effects

  • In short-term studies, antidepressants increased the risk of suicidal thinking and behavior in children, adolescents, and young adults (under 24 years old) taking antidepressants for major depressive disorders and other psychiatric illnesses. Patients should be monitored closely for changes in behavior, clinical worsening, and suicidal tendencies; this should be done during the initial 1-2 months of therapy and dosage adjustments. The patient's family should communicate any abrupt changes in behavior to the health-care provider
  • See "What Are Side Effects Associated with Using Fluoxetine?"

Long-Term Effects

  • Bone fractures have been associated with antidepressant therapy, consider the possibility of bone fracture when patient presents with bone pain
  • See "What Are Side Effects Associated with Using Fluoxetine?"

Cautions

  • Clinical worsening and suicidal ideation may occur despite medication in adolescents and young adults (aged 18-24 years)
  • Risk of serotonin syndrome when used with other strong serotonergic drugs
  • Risk of bleeding (GI and other) when used in combination with anti-inflammatory medications, aspirin, or drugs affecting coagulation; may impair platelet aggregation
  • Activation of mania or hypomania, screen for bipolar disorder
  • Fluoxetine therapy has been associated with occurrence of rash and allergic reaction, including inflammation of blood vessels; discontinue if they occur
  • Bone fractures have been associated with antidepressant therapy, consider possibility of bone fracture when patient presents with bone pain
  • May cause or exacerbate sexual dysfunction
  • Use caution in patients with risk for QT prolongation, including congenital long QT syndrome, history of prolonged QT, or history of prolonged QT; QT prolongation and ventricular arrhythmia, including torsade de pointes
  • Low blood sodium reported with use, consider discontinuation if symptomatic occurs
  • Use caution in patients with history of seizure disorders
  • May prolong QT interval and cause ventricular arrhythmia, including torsade de pointes
  • May cause nervousness, anxiety, insomnia, or loss of appetite
  • Risk of dilation of the pupil of the eye; may trigger angle closure attack in patients with angle closure glaucoma with anatomically narrow angles without a patent surgically removing a part of the iris (iridectomy)
  • Hypoglycemia reported; may alter glycemic control in patients with diabetes
  • Pregnancy: Conflicting evidence regarding use of SSRIs during pregnancy and increased risk of persistent pulmonary hypertension of the newborn, or PPHN. Risk of complications in neonates exposed to SNRIs/SSRIs late in third trimester (feeding difficulties, irritability, and respiratory problems)
  • Wait 1 week after discontinuation of Prozac before starting Prozac Weekly
  • Gradually decrease dose when discontinuing. Fluoxetine has long half-life, decrease in dose will not be fully reflected in plasma for several weeks
  • In conditions that predispose to QT prolongation and ventricular arrhythmia; include concomitant use of drugs that prolong the QT interval; hypokalemia or hypomagnesemia; recent myocardial infarction, uncompensated heart failure, bradyarrhythmias, and other significant arrhythmias
  • Consider ECG assessment and periodic ECG monitoring if initiating treatment with fluoxetine in patients with risk factors for QT prolongation and ventricular arrhythmia; consider discontinuing fluoxetine and obtaining a cardiac evaluation if patients develop signs or symptoms consistent with ventricular arrhythmia

Pregnancy and Lactation

  • Use fluoxetine during pregnancy with caution if benefits outweigh risks. Animal studies show risk and human studies are not available or neither animal nor human studies were done
  • Treatment of pregnant women during the first trimester: There are no adequate and well-controlled clinical studies on the use of fluoxetine in pregnant women, but 1 prospective cohort study conducted by the European Network of Teratology Information Services reported an increased risk of cardiovascular malformations in infants born to women (N = 253) exposed to fluoxetine during the first trimester of pregnancy, compared with infants of women (N = 1359) who were not exposed to fluoxetine. Use late in the third trimester associated with complications in newborns and may require prolonged hospitalization, respiratory support, and tube feeding
  • When treating a pregnant woman with fluoxetine, physician should carefully consider trimester both for the potential risks of taking an SSRI, along with the established benefits of treating depression with an antidepressant; the decision can only be made on a case by case basis
  • A study of nearly 28,000 women taking SSRIs confirmed 2 previously reported birth defects associated with fluoxetine - heart wall defects and craniosynostosis (BMJ 2015; 351:h3190)
  • Persistent pulmonary hypertension of the newborn: (PPHN)
    • Potential risk of PPHN when used during pregnancy. Initial public health advisory, in 2006, was based on a single published study; since then, there have been conflicting findings from new studies, making it unclear whether the use of SSRIs during pregnancy can cause PPHN. The FDA has reviewed the new study results and has concluded that, given the conflicting results from different studies, it is premature to reach any conclusion about a possible link between SSRI use in pregnancy and PPHN
    • FDA recommendation: The FDA advises health-care professionals not to alter their current clinical practice of treating depression during pregnancy and to report any adverse events to the FDA MedWatch program. A meta-analysis of 7 observational studies, found exposure to SSRIs in late pregnancy (after 20 weeks' gestation) more than doubled the risk of PPHN that could not be explained by other etiologies (congenital malformations or meconium aspiration) (BMJ 2014;348:f6932)
    • Fluoxetine is excreted in breast milk, avoid use when lactating. The American Academy of Pediatrics (AAP) states effect on nursing infants is unknown but may be of concern