Escitalopram is the pure S-enantiomer (single isomer) of the racemic bicyclic phthalane derivative citalopram. Escitalopram oxalate is designated S-(+)-1-[3-(dimethylamino)propyl]-1-( p -fluorophenyl)-5-phthalancarbonitrile oxalate with the molecular formula:

C₂₀H₂₂FN₂O⁺ C₂HO₄^-

and the molecular weight is 414.40.

Escitalopram oxalate is derived from the drug citalopram which is made up of two mirror-image isomers, only one of which is thought to be an effective medication. Lundbeck has split the isomers apart, taken the active isomer and has licensed it as the new drug 'escitalopram'.

It is notable that escitalopram was released shortly before the patent for citalopram was due to expire. The expiration of a patent means other companies can legally produce cheaper generic versions. Escitalopram is subject to a new patent. Critics have argued that escitalopram, and the subsequent marketing campaign to persuade mental health professionals to prescribe it, is a cynical ploy to promote sales of a virtually identical but considerably more expensive drug. In defence of the new drug, Lundbeck have claimed that the drug has additional benefits over the older citalopram and other antidepressant drugs on the market.

Externals links

Pharmacological information and studies on escitalopram:

• http://www.biopsychiatry.com/escitalopram.html
• http://www.rxlist.com/cgi/generic/lexapro.htm

Lundbeck official websites for escitalopram under their trade names Cipralex and Lexapro:

• http://www.cipralex.com
• http://www.lexapro.com

"'Radical' drug criticised as only a commercial device" article from UK paper, The Guardian:

• http://society.guardian.co.uk/mentalhealth/story/0,8150,738940,00.html

"Lexapro feedback" page from Depression Blog:

• http://www.depressionblog.com/archives/cat_lexapro.shtml