Posted by chemist on July 7, 2004, at 22:57:11
In reply to chemical difference between paxil and lexapro, posted by shadowmon on July 4, 2004, at 4:23:42
> Does anyone know the difference between what paxil afects and what lexapr affects? Is there any difference?
hello there, chemist here...lexapro is the (S) enantiomer of citalopram. one of the posters refers to the other enantiomer as being ``inactive,'' but that is not correct: the (R) enantiomer of citalopram is the cause of the unwanted side effects of the racemate (R,S)-citalopram (celexa) and the binding affinity is about 1% that of the (S) enantiomer, but it is hardly inactive. the downside is that along with unwanted side effects some of the *wanted* side effects go away, such as inhibition of reuptake of dopamine and norepinephrine (minor). as for paroxetine, it reads more or less like lexapro with the exception that there are so many nasty problems due to the route by which it is metabolized, specifically the cyp4502D6 isoenzyme. lexapro/celexa do not inhibit, act as substrates, or autoinduce cyp4502D6, which is one of the enzymes that many other drugs are metabolized by, anbd hence the potential for interactions is increased. also, paxil just plain appears to have a lengthy track record of unwanted side-effects, regardless of the SSRI activity.....hope theis helps, and all the best, chemist
poster:chemist
thread:362933
URL: http://www.dr-bob.org/babble/20040704/msgs/363891.html