When does patent run out on Lexapro?

Answer 1

Lexapro patent expires in March 2012. So not available as a generic. Its "sister" drug is Celexa, which has been off patent since 2003. Ask your Dr. for Celexa. A 90 day supply of generic Celexa is about $15 at places like Wallgreens or Walmart. Escitalopram, which is the trade/brand name of Lexapro is a “purer” form of Celexa (generically known as Citalopram). Lexapro (i.e. Escitalopram) is the (S) enatntiomer of racemic Citalopram (i.e. Celexa). In chemistry, enantiomers are compounds (such as crystals or molecules) which are non-superimposable mirror images of each other. They share the same molecular formula and sequence of bonded atoms, but differ structurally. The chemical formula (i.e. recipe) of both Lexipro and Celexa is the same: C20 H21 F N2 0 (20 carbons, 21 hydrogens, 1 fluorine, 2 nitrogens, and 1 oxygen molecule). But the way they are assembled is slightly different. Your hands (and feet) are examples of Enantiomers. Left and right hands are "the same" but opposite in their structure. Enantiomers have the same chemical and physical properties (such as melting points, boiling points, heat of combustion etc.), but the way they interact may be different. The left handed molecule may be more potent than the right. Maybe the right handed molecule does not work at all. In some cases one molecule may even be harmful, while the enantiomer is beneficial. Think about how your feet feel if you put them in the wrong shoes. You can wear a left shoe on your right foot or a left glove on your right hand, but it won’t fit well. In chemistry, a racemic mixture is a mix of both left- and right-handed molecules. Getting back to Lexapro vs Celexa. Celexa is a mix of both R-citalopram & S-citalopram. While Lexapro is just S-citalopram. In studies, Lundbeck, the pharmaceutical company which makes both Celexa and Lexapro showed that the S-citalopram molecule has a higher affinity for the serotonin receptor. So by removing the R-citalopram from the mixture, Lundbeck created a more efficient drug. In theory, a smaller dose of Lexipro would have the same effect as a larger dose of Celexa. In reality, pharmaceutical companies do this to extend the market life and squeeze as much profit out of a drug. The patent for Celexa expired in 2003, so Lundbeck “purified” Celexa and were able to re-patent the formula as a new drug, Lexapro. The patent for Lexapro expires in 2012. Although Lundbeck showed Lexapro works (a little) better than Celexa (and gained a new patent) most independent “real life” studies (i.e. asking humans, not following monkeys in a lab) show Celexa works pretty much just as well as Lexapro. I tried to be concise without being confusing.