<p>Escitalopram is an orally administered selective serotonin reuptake inhibitor (SSRI). Escitalopram is the pure S-enantiomer of the racemic bicyclic phthalate derivative citalopram. Escitalopram is at least 100 fold more potent than the R-enantiomer with respect to inhibition of 5-HT reuptake. Escitalopram has no or very low affinity for serotonergic or other receptors including alpha- and beta-adrenergic Dopamine, Histamine, Muscarinic and benzodiazepine receptors.</p>