About Lexapro(Escitalopram)

Escitalopram (Lexapro, Cipralex, Sipralexa and Seroplex) is an antidepressant of the selective serotonin reuptake inhibitor (SSRI) class. It is approved for the treatment of major depressive disorder and generalized anxiety disorder; other indications include social anxiety disorder, panic disorder and obsessive compulsive disorder. Escitalopram is the S-stereoisomer (enantiomer) of the earlier Lundbeck drug citalopram (Celexa), hence the name (es-citalopram). Escitalopram is noted for its high selectivity of serotonin reuptake inhibition and, as a result, relative mildness of the side effects. The drug is marketed in the US under the name Lexapro by Forest Laboratories and elsewhere under various brand names by Lundbeck.

Pharmacology

Escitalopram acts by increasing intrasynaptic levels of the neurotransmitter serotonin by blocking the re-uptake of the neurotransmitter into the neuron. Escitalopram has the highest affinity to the human serotonin transporter (SERT). Remarkably, another enantiomer of citalopram (R-citalopram) counteracts to a certain degree the serotonin enhancing action of escitalopram. As a result, escitalopram is a more potent antidepressant than citalopram, which is a mixture of escitalopram and R-citalopram. In order to explain this phenomenon, Sanchez proposed that escitalopram enhances its own binding via an additional interaction with another allosteric site on the transporter. Further research by the same group showed that R-citalopram also enhances binding of escitalopram, and therefore the allosteric interaction cannot explain the observed counteracting effect. However, in the most recent paper the same authors again reversed their findings and reported that R-citalopram decreases binding of escitalopram to the transporter. Although allosteric binding of escitalopram to the serotonin transporter is of unquestionable research interest, its clinical relevance is unclear since binding of escitalopram to the allosteric site is at least 1000 times weaker than to the primary binding site.

Dosing

The recommended dosage of Lexapro is 10-20 mg a day. Exceptions include the elderly, who should only take up to 10 mg a day, and pregnant women in their third trimester should not use Lexapro at all. As both Generalized Anxiety Disorder (GAD) and Depression are both considered chronic conditions, treatment is recommended for several months. However, the efficacy of Lexapro over long periods of time has not been studied, therefore consistent reevaluation of the treatment is recommended for longer periods of treatment.

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