I do not need Prozac... But let me learn how Fluoxetine works!

Fluoxetine: Sold as Prozac, Sarafem, Fontex etc.

Image Courtesy: "Depressants ." Human Diseases & Conditions. N.p., 2011. Web. 16 Feb. 2011.

This is an antidepressant of the selective serotonin reuptake inhibitor (SSRI) class

Fluoxetine is approved for the treatment of 

Major depression (including pediatric depression),

Obsessive-compulsive disorder (in both adult and pediatric populations), 

Bulimia nervosa, 

Panic disorder and 

Premenstrual dysphoric disorder.

Fluoxetine's mechanism of action is primarily that of an SSRI. 

SSRIs are believed to increase the extracellular level of the neurotransmitter serotonin by inhibiting its reuptake into the presynaptic cell, increasing the level of serotonin in the synaptic cleft available to bind to the postsynaptic receptor.

The bioavailability of fluoxetine is relatively high (72%), and peak plasma concentrations are reached in 6 to 8 hours. 

Fluoxetine is metabolized in the liver by isoenzymes of the cytochrome P450 system, including CYP2D6. The role of GYP in the metabolism of fluoxetine may be clinically important, as there is great genetic variability in the function of this enzyme among people. Only one metabolite of fluoxetine, norfluoxetine (N-demethylated fluoxetine), is biologically active. Steady concentration in the blood is achieved only after four weeks The brain concentration of fluoxetine and its metabolites keeps increasing through at least the first five weeks of treatment. That means that the full benefits of the current dose a patient receives are not realized for at least a month since its initiation Likewise, complete excretion of the drug may take several weeks.

Video: Youtube

Major Depressive Disorder in Children and Adolescents

Source: http://www.uspreventiveservicestaskforce.org/uspstf/uspschdepr.htm#summary
U.S. Preventive Services Task Force (USPSTF) recommendations on screening for depression in children and adolescents

Summary of Recommendations

• The USPSTF recommends screening of adolescents (12-18 years of age) for major depressive disorder (MDD) when systems are in place to ensure accurate diagnosis, psychotherapy (cognitive-behavioral or interpersonal), and follow-up. 
• The USPSTF concludes that the current evidence is insufficient to assess the balance of benefits and harms of screening of children (7-11 years of age).
• Benefits of Detection and Early Intervention
• Adolescents (12-18 years of age): The USPSTF found adequate evidence that treatment in adolescents with selective serotonin reuptake inhibitors (SSRIs -  fluoxetine) ), psychotherapy, and combined therapy (SSRIs and psychotherapy) results in decreases in MDD symptoms.
• Children (7-11 years of age): The USPSTF found inadequate evidence to support the benefits of treatment in children. SSRIs (fluoxetine) reduce MDD symptoms in children; however, there are limited data on the benefits of psychotherapy and the benefits of psychotherapy plus SSRIs in children.
• Assessment of Risk: Important risk factors that can be assessed relatively accurately and reliably include parental depression, having comorbid mental health or chronic medical conditions, and having experienced a major negative life event.

Screening Tests: Instruments developed for primary care (Patient Health Questionnaire for Adolescents [PHQ-A] and the Beck Depression Inventory-Primary Care Version [BDI-PC]) have been used successfully in adolescents. 

There are limited data describing the accuracy of using MDD screening instruments in younger children (7-11 years of age).

Treatment: Among pharmacotherapies available for the treatment of MDD in children and adolescents, SSRIs have been found to be efficacious. Treating depressed youth with SSRIs is associated with an increased risk of suicidality and, therefore, should only be considered if judicious clinical monitoring is possible. Psychotherapy trials indicate that a variety of psychotherapy types are efficacious among adolescents (including cognitive-behavioral and interpersonal therapies). Harms of psychotherapy are felt to be small.

Update of Previous USPSTF Recommendation

This recommendation updates the previous recommendation released in 2002. The major change in the current recommendation is that the USPSTF now recommends screening of adolescents (12-18 years of age) for MDD when systems are in place to ensure accurate diagnosis, psychotherapy (eg, cognitive-behavioral, interpersonal), and follow-up. In 2002, the USPSTF concluded that there was insufficient evidence to recommend for or against routine screening of children or adolescents for MDD (I recommendation). The basis for this change in recommendation for adolescents is a result of new evidence that demonstrates treatment benefit.