Escitalopram: better treatment for depression is through the looking glass

Abstract

Depression remains a common and often devastating illness. With the introduction of the selective serotonin reuptake inhibitors in the 1980s, patients were afforded treatment for depression that was both safer and better tolerated than any prior treatment modality offered. Although selective serotonin reuptake inhibitors quickly became the most widely used medications for the treatment of depression, no single agent has been recognized as an obvious first-line choice. Chirality potentially offers one method to improve upon the selective serotonin reuptake inhibitor class. For racemic compounds that differ in stereospecificity, separation into single enantiomers can result in significant changes in potency, tolerability and efficacy. One of the most widely prescribed selective serotonin reuptake inhibitors is citalopram, which exists as a racemic mixture of R- and S-enantiomers. The S-enantiomer escitalopram (Cipralex®, Lundbeck) is the therapeutically active portion of the parent compound and has a proven antidepressant efficacy. The R-enantiomer lacks activity as an antidepressant and has been shown to inhibit the effect of the S-enantiomer when the two are combined. Escitalopram is the most selective member of its class and with minimal effects on the cytochrome P450 system, has a negligible potential for drug–drug interactions. In placebo-controlled trials, escitalopram has consistently demonstrated symptomatic improvement as early as the first to second week of treatment. In addition to antidepressant efficacy, escitalopram also appears to exhibit significant anxiolytic properties. It has also shown efficacy in treating panic disorder and generalized and social anxiety disorders. This is advantageous as many patients who suffer from depression also experience comorbid anxiety disorders.