Fluoxetine hydrochloride (Prozac) is an antidepressant of the selective serotonin reuptake inhibitor (SSRI) class.

Fluoxetine is approved for the treatment of clinical depression (including pediatric depression), obsessive-compulsive disorder (in both adult and pediatric populations), bulimia nervosa, panic disorder and premenstrual dysphoric disorder.Other indications include hypochondriasis and body dysmorphic disorder.

Despite the availability of newer agents, it remains extremely popular. Over 23.1 million prescriptions for generic formulations of fluoxetine were filled in the United States in 2006, making it the third most prescribed antidepressant.

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

Fluoxetine is metabolized in the liver by isoenzymes of the cytochrome P450 system, including CYP2D6.The role of CYP2D6 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 (demethylated fluoxetine), is biologically active.

Fluoxetine is cleared slowly from the body; its elimination half-life ranges from 1 to 3 days—after a single dose—to 4 to 6 days (after long-term use) in healthy adults, and is prolonged in those with liver disease. The half-life of norfluoxetine is longer (16 days after long-term use).Complete excretion of the drug may take several weeks.

Studies comparing fluoxetine 20, 40, and 60 mg/day to placebo indicate that 20 mg/day is sufficient to obtain a satisfactory response in major depressive disorder in most cases. Consequently, a dose of 20 mg/day, administered in the morning, is recommended as the initial dose.

Anxiety, agitation, panic attacks, insomnia, irritability, hostility, aggressiveness, impulsivity, hypomania, and mania, have been reported in adult and pediatric patients being treated with Prozac for major depressive disorder as well as for other indications, both psychiatric and non-psychiatric. If these symptoms occur the medication should be reduced or cautiously withdrawn.

Since the introduction of fluoxetine, systemic events, possibly related to vasculitis and including lupus-like syndrome, have developed in patients with rash. Although these events are rare, they may be serious, involving the lung, kidney, or liver. Death has been reported to occur in association with these systemic events.

The simultaneous use of fluoxetine with triptans, tramadol or other serotonergic agents can result in a rare, but potentially life-threatening adverse drug reaction called Serotonin syndrome.

SSRIs such as fluoxetine have been associated with tardive dyskinesia and akathisia, among other extrapyramidal symptoms more commonly associated with antipsychotics.

Source : www.wikipedia.org