![[dr. bob]](/dr-bob-sm.gif)
Dr. Bob is Robert Hsiung, MD,
bob@dr-bob.orgShown: posts 74 to 98 of 8406. Go back in thread:
Posted by Maximus on August 19, 2002, at 17:26:48
In reply to Re: Lexapro is no different from Celexa, posted by dr. dave on August 19, 2002, at 4:52:24
Posted by Patson on August 19, 2002, at 23:10:54
In reply to Re: Lexapro is no different from Celexa, posted by dr. dave on August 19, 2002, at 4:52:24
I might guess that you sound an awful lot like a friend of mine who is a glaxo rep.... He's been telling me the same thing....
> The Danish Institute for Rational Pharmacotherapy has reviewed all of the available data comparing Lexapro and Celexa and has concluded there is no convincing evidence for any difference in tolerability, efficacy, or anything else. This is the only other independent review of the data apart from Micromedex I am aware of. It is only those linked with the manufacturers of Lexapro that are talking it up, and the only two independent reviews come to the same conclusion - there is no real difference. The story is on the Reuters news website.
>
>
Posted by Patson on August 19, 2002, at 23:18:08
In reply to Re: Lexapro side-effects » dr. dave, posted by Ritch on June 19, 2002, at 9:11:56
> > Just for accuracy of information... Celexa's patent in the US won't expire until 2003. There is also a six month exclusivity extension due to clinical studies conducted in children. In addition, a generic citalopram would take about 18 months to get approval from the FDA. A generic equivalent for Celexa then wouldn't be available until sometime in 2005.
> > The research shows Lexapro has no significant benefit over Celexa in terms of side-effects. People taking Lexapro 20mg report side-effects at the same rate as those on Celexa 40mg (86%).
> >
> > In the same study more people stopped taking Lexapro 20mg because of side-effects than those taking Celexa 40mg (10.4% vs 8.8%), but this difference was not statistically significant.
> >
> > The reason for this is that Lexapro is to all intents and purposes the same thing as Celexa but re-branded and re-patented. There is no evidence of the R-citalopram component they have removed doing anything of significance pharmacologically. To understand this 'new' drug you have to understand that the patent on Celexa just ran out, but the manufacturers can effectively renew the patent by isolating the active component and re-branding it.
> >
> > See more at http://www.guardian.co.uk/Archive/Article/0,4273,4434943,00.html
> >
> > The critical comments in the article are mine.
>
>
> Hi,
>
> Thanks for the article. It wouldn't surprise me a whole lot if the only advantage it winds up having is less medicine for your liver to clear out! I have always wondered about the "mechanism" versus "medicine" distinction between antidepressants when it comes to how they work and side-effects. SSRI's all tend to cause many similar wanted and unwanted effects. If they isolated the *active* isomer, then they probably isolated something that is *more* likely to cause typical SSRI wanted and *unwanted* effeects. It will be interesting to see the comments made here when people start "reporting" in about it.
>
> Mitch
>
Posted by pharmrep on August 19, 2002, at 23:46:50
In reply to Re: Lexapro side-effects, posted by Patson on August 19, 2002, at 23:18:08
> > > Just for accuracy of information... Celexa's patent in the US won't expire until 2003. There is also a six month exclusivity extension due to clinical studies conducted in children. In addition, a generic citalopram would take about 18 months to get approval from the FDA. A generic equivalent for Celexa then wouldn't be available until sometime in 2005.
>
>
> > > The research shows Lexapro has no significant benefit over Celexa in terms of side-effects. People taking Lexapro 20mg report side-effects at the same rate as those on Celexa 40mg (86%).
> > >
> > > In the same study more people stopped taking Lexapro 20mg because of side-effects than those taking Celexa 40mg (10.4% vs 8.8%), but this difference was not statistically significant.
> > >
> > > The reason for this is that Lexapro is to all intents and purposes the same thing as Celexa but re-branded and re-patented. There is no evidence of the R-citalopram component they have removed doing anything of significance pharmacologically. To understand this 'new' drug you have to understand that the patent on Celexa just ran out, but the manufacturers can effectively renew the patent by isolating the active component and re-branding it.
> > >
> > > See more at http://www.guardian.co.uk/Archive/Article/0,4273,4434943,00.html
> > >
> > > The critical comments in the article are mine.
> >
> >
> > Hi,
> >
> > Thanks for the article. It wouldn't surprise me a whole lot if the only advantage it winds up having is less medicine for your liver to clear out! I have always wondered about the "mechanism" versus "medicine" distinction between antidepressants when it comes to how they work and side-effects. SSRI's all tend to cause many similar wanted and unwanted effects. If they isolated the *active* isomer, then they probably isolated something that is *more* likely to cause typical SSRI wanted and *unwanted* effeects. It will be interesting to see the comments made here when people start "reporting" in about it.
> >
> > Mitch
> >
*** i dont get it...in 1 breath..the generic not being available til 2005 is stated, and in the next "patent beating" is thrown out? pick one (hint...its not patent beat) Next...the starting dose for Lex is 10mg...slightly higher in comparison to the higher titrated 40mg of Celexa...compare those side-effects equally, not the higher 20mg of Lex. (and its still "comparable to placebo" per the FDA)...And to understand this "new" drug is to know your isomer science..not this patent crap. (the Nobel Prize for chemistry was won in 2001 for the scientists who developed the technology Forest is using to create Lexapro...and at a lower cost than Celexa too.)
PS....you're right Mitch...only time will tell and then the truth will be known....so lets just watch and see.
Posted by pharmrep on August 20, 2002, at 0:06:06
In reply to Re: Lexapro is no different from Celexa, posted by Patson on August 19, 2002, at 23:10:54
> I might guess that you sound an awful lot like a friend of mine who is a glaxo rep.... He's been telling me the same thing....
>
> > The Danish Institute for Rational Pharmacotherapy has reviewed all of the available data comparing Lexapro and Celexa and has concluded there is no convincing evidence for any difference in tolerability, efficacy, or anything else. This is the only other independent review of the data apart from Micromedex I am aware of. It is only those linked with the manufacturers of Lexapro that are talking it up, and the only two independent reviews come to the same conclusion - there is no real difference. The story is on the Reuters news website.
> >
> >
> ** I have never seen so much hype. I dont know what the Danes are looking at. There are 9 studies so far, and every one shows Lexapro at an advantage. There are more studies on the way...most new drugs only look at placebo, but Lex did head to head right away...do you really think Forest would hang its hat on a drug 3 years before a proven winner (Celexa) if it wasnt better?
PS your Glaxo rep just went through what your describing...paxil cr is the same molecule as paxil...only a lower dose, and different delivery...but the same drug---exactly the same (and passed FDA 3 years ago, but was only released this year..when 1st paxil expires..hows that for patent beat!)..Lexapro is not the same as Celexa... stop the hype and read the studies on your own before making an "informed" decision for yourself.
Posted by dr. dave on August 20, 2002, at 5:21:03
In reply to Re: Lexapro is different » Patson, posted by pharmrep on August 20, 2002, at 0:06:06
'Celexa' 20mg is 10mg s-isomer and 10 mg r-isomer. The r-isomer is effectively inert as an SSRI or anything else. Celexa only works because of the 10mg s-isomer in it. 'Lexapro' is the 10mg s-isomer on its own. It's pretty hard and expensive to produce separately, and it's a funny thing to do when the r-isomer has virtually no pharmacological action at all.
Lexapro 10mg is Celexa 20mg with 10 mg of an inert substance expensively removed.
Posted by dr. dave on August 20, 2002, at 5:31:12
In reply to How do you act on that information? » dr. dave, posted by Anyuser on August 19, 2002, at 11:12:18
I am a practicing psychiatrist and I prescribe Celexa widely. I have a responsibility not to prescribe everything that is claimed to be new and improved until I have some decent scientific information to justify changing from using drugs that I am familiar with.
It is true that Zoloft is more effective than Paxil for some people (as an example), and we don't know why, but we can fairly safely say that it is because they are different drugs which work slightly differently. My puzzlement about claims that Lexapro works better than Celexa are founded on the fact that the active element is the exact same molecule, atom for atom.
The financial issue is relevant as there will always be some limit on the funds available for treating mental disorder. I think that as much benefit should be obtained from those resources as possible. I don't think we can afford to waste money. Paying significantly more for a drug on the basis that the manufacturers think it is better is not justifiable unless there is decent evidence to back that claim up. To date that evidence does not exist.
Posted by dr. dave on August 20, 2002, at 5:48:24
In reply to Re: Lexapro is different » Patson, posted by pharmrep on August 20, 2002, at 0:06:06
I'm sure you believe Lexapro is different, pharmrep, but can't you see that you might not be in a position to make the most balanced of judgements on the evidence? It is not really convincing to try to persuade people it is different just by insisting that it is.
Turning to the isomer science, why are there no plausible theories at all as to how removing r-citalopram could increase speed of onset and efficacy? We know it doesn't affect the pharmacokinetics of s-citalopram and we know that it has about 1/30th the affinity for the serotonin reuptake transporter of s-citalopram so it can't be competing at the binding site. It really is inert. Lundbeck, who developed the drug, still had no theory to back up the claim that r-citalopram impedes s-citalopram's activity when I last spoke to them. Does Forrest?
I would be more than happy to discuss the deficiencies in the published papers if you wish. Independent reviews of the evidence wouldn't both come to the same conclusion for no reason.
Posted by Ritch on August 20, 2002, at 9:37:03
In reply to Citalopram pharmacology - Mitch, posted by dr. dave on August 20, 2002, at 5:21:03
> 'Celexa' 20mg is 10mg s-isomer and 10 mg r-isomer. The r-isomer is effectively inert as an SSRI or anything else. Celexa only works because of the 10mg s-isomer in it. 'Lexapro' is the 10mg s-isomer on its own. It's pretty hard and expensive to produce separately, and it's a funny thing to do when the r-isomer has virtually no pharmacological action at all.
>
> Lexapro 10mg is Celexa 20mg with 10 mg of an inert substance expensively removed.
<from other post>
We know it doesn't affect the pharmacokinetics of s-citalopram and we know that it has about 1/30th the affinity for the serotonin reuptake transporter of s-citalopram so it can't be competing at the binding site.
Thanks for those added tidbits of information! I knew that r-citalopram had less affinity for the serotonin reuptake transporter, but not 1/30th... Then, the only thing left to consider is the notion of r-citalopram *causing* side-effects (commonly associated with SSRI's) with little affinity for the serotonin reuptake transporter.Mitch
Posted by pharmrep on August 20, 2002, at 11:16:11
In reply to Citalopram pharmacology - Mitch, posted by dr. dave on August 20, 2002, at 5:21:03
> 'Celexa' 20mg is 10mg s-isomer and 10 mg r-isomer. The r-isomer is effectively inert as an SSRI or anything else. Celexa only works because of the 10mg s-isomer in it. 'Lexapro' is the 10mg s-isomer on its own. It's pretty hard and expensive to produce separately, and it's a funny thing to do when the r-isomer has virtually no pharmacological action at all.
>
> Lexapro 10mg is Celexa 20mg with 10 mg of an inert substance expensively removed.*** i'm afraid your wrong...if you look at the studies, you'll see that 10mg Lex is 40mg of Celexa, not 20mg....It is not hard, but a new technology that has allowed the separation of the 2 isomers, and it is not that expensive...in fact Lexapro will be less than Celexa...Dr Dave...where do you get your info?
Posted by pharmrep on August 20, 2002, at 11:23:58
In reply to Re: How do you act on that information?, posted by dr. dave on August 20, 2002, at 5:31:12
> I am a practicing psychiatrist and I prescribe Celexa widely. I have a responsibility not to prescribe everything that is claimed to be new and improved until I have some decent scientific information to justify changing from using drugs that I am familiar with.
>
> It is true that Zoloft is more effective than Paxil for some people (as an example), and we don't know why, but we can fairly safely say that it is because they are different drugs which work slightly differently. My puzzlement about claims that Lexapro works better than Celexa are founded on the fact that the active element is the exact same molecule, atom for atom.
>
> The financial issue is relevant as there will always be some limit on the funds available for treating mental disorder. I think that as much benefit should be obtained from those resources as possible. I don't think we can afford to waste money. Paying significantly more for a drug on the basis that the manufacturers think it is better is not justifiable unless there is decent evidence to back that claim up. To date that evidence does not exist.**** I agree that decisions should be based on scientific evidence, and also what reality shows in your pracitice. Lexapro is more than just 1/2 of Celexa, in the studies, it is shown that the r-citalopram was actually inhibiting the s-citalopram from its full potential. As far as cost...Lexapro (a new drug) will be less than Celexa....who told you otherwise? (Lexapro competitors?) There are several studies out that show evidence supporting all the claims you say dont exist..have you read them? Do you know them? I can get them for you if you like so you can make a more "informed" decision.
Posted by Anyuser on August 20, 2002, at 11:31:53
In reply to Re: Dr, where do you get that information? » dr. dave, posted by pharmrep on August 20, 2002, at 11:23:58
Posted by pharmrep on August 20, 2002, at 11:38:30
In reply to Lexapro still isn't different - pharmrep, posted by dr. dave on August 20, 2002, at 5:48:24
> I'm sure you believe Lexapro is different, pharmrep, but can't you see that you might not be in a position to make the most balanced of judgements on the evidence? It is not really convincing to try to persuade people it is different just by insisting that it is.
>
> Turning to the isomer science, why are there no plausible theories at all as to how removing r-citalopram could increase speed of onset and efficacy? We know it doesn't affect the pharmacokinetics of s-citalopram and we know that it has about 1/30th the affinity for the serotonin reuptake transporter of s-citalopram so it can't be competing at the binding site. It really is inert. Lundbeck, who developed the drug, still had no theory to back up the claim that r-citalopram impedes s-citalopram's activity when I last spoke to them. Does Forrest?
>
> I would be more than happy to discuss the deficiencies in the published papers if you wish. Independent reviews of the evidence wouldn't both come to the same conclusion for no reason.*** Yes, and I've gone through credibilty before here. I find it interesting...all the opinions that are subjectively based. If I see statements that are completely one-sided...I like to jump in. Especially ones I have facts on. I have plenty of studies to back the differences up...do you? The 9 done all show statistically significant differences, so what are you referring to when you make your statements. (Did you participate in "early studies?") I am guessing you havent read the studies... primarily because you insist there is no pharmacokinetics in r-citalopram. Yes is does not help in the treatment of depression, but it definitely was inhibiting s-citalopram (ie...r attaches to histomine receptors sites which can cause somnolence). And Lundbeck just spoke to Forest in late June in Atlanta (I was there) about the "US" studies and how more was uncovered than in the European studies. Cool, I would love to chat with you...what city are you in?
Posted by pharmrep on August 20, 2002, at 11:42:31
In reply to Re: Citalopram pharmacology -Dr. Dave, posted by Ritch on August 20, 2002, at 9:37:03
NO.....10mg Lex is 40mg of Celexa...trust me.
Posted by Anyuser on August 20, 2002, at 12:17:02
In reply to Re: Citalopram pharmacology -Dr. Dave » Ritch, posted by pharmrep on August 20, 2002, at 11:42:31
The prescribing info recommends 10mg, period, including elderly patients and those with impaired livers or kidneys. It is interesting to note that the prescribing info says there seems to be no benefit to 20mg over 10mg.
I'm curious, why even bother to manufacturer 5mg pills? The 10 mg pills are scored. Has any testing been done on the 5mg dose?
Posted by Mr.Scott on August 20, 2002, at 13:00:21
In reply to Re: Citalopram pharmacology -Dr. Dave » Ritch, posted by pharmrep on August 20, 2002, at 11:42:31
I am reposting this because even though I haven't picked out anything in your posts that cross any lines you are by definition biased. If your not here for help with a mental disorder it's kind of silly that your here at all. Yes for many, Lexapro will work as an antidepressant, and for some it will not, and other still will have problems with it entirely.. To think it will be light years ahead of anything currently available is preposterous. Everyone is different and your studies with 10,000 patients by doctors who are paid in grants and whose funding has been "underwritten in educational disguise" have consistently failed to elucidate the whole picture on any of these meds when used on a given individual. I would be a no see doc if I was one. Donuts for my office staff and samples for my patients, otherwise... well anyways my post below is what Forest's real goal is. If a few suffering people can benefit than great.
Citalopram is the #1 most used AD in the world
Forest has the marketing rights to Citalopram in the US under Celexa, but not in Europe where it actually is the number 1 prescribed antidepressant. In Europe and all other non-us companies, citalopram is owned by various other companies.
Forest will have full international rights to Lexapro and will launch a campaign to convert the entire world on Citalopram (Celexa and other names) to the new improved Leaxapro. Much more marketshare and money.
Believe me when I tell you that there is not a single person in the pharmaceutical industry who cares about you and your depression as much as they care about you and your money. Their motivations are always 100% based on bottom line revenue. Don't ever think for a second they have any other motivation whatsoever. Altruism is not welcome in this industry. Thats what Church on Sunday is for...
Scott
Posted by Ritch on August 20, 2002, at 13:10:54
In reply to Re: Citalopram pharmacology -Dr. Dave » Ritch, posted by pharmrep on August 20, 2002, at 11:42:31
> NO.....10mg Lex is 40mg of Celexa...trust me.
PharmRep,
I wished somebody would do receptor affinity profiling for r- and s- citalopram separately. If the r- isomer has little affinity for the serotonin reuptake transporter, it (the r-isomer) possibly could have an increased affinity for other receptors involved with side effects. I did find it interesting in the micromedex link posted a while ago that the half-life of s-citalopram is about 22 hrs and that the half-life of s+r-citalopram is about 35 hrs. (If that is inaccurate-please somebody correct me).
thanks,Mitch
Posted by pharmrep on August 20, 2002, at 14:40:38
In reply to Question re dose » pharmrep, posted by Anyuser on August 20, 2002, at 12:17:02
> The prescribing info recommends 10mg, period, including elderly patients and those with impaired livers or kidneys. It is interesting to note that the prescribing info says there seems to be no benefit to 20mg over 10mg.
>
> I'm curious, why even bother to manufacturer 5mg pills? The 10 mg pills are scored. Has any testing been done on the 5mg dose?no...not yet...10 is the starting and maintenance dose...20 if 10 looks a little "light." What do you mean 20mg no benefit? where did you read this?
Posted by pharmrep on August 20, 2002, at 14:52:48
In reply to Hey Pharm-rep, posted by Mr.Scott on August 20, 2002, at 13:00:21
> I am reposting this because even though I haven't picked out anything in your posts that cross any lines you are by definition biased. If your not here for help with a mental disorder it's kind of silly that your here at all. Yes for many, Lexapro will work as an antidepressant, and for some it will not, and other still will have problems with it entirely.. To think it will be light years ahead of anything currently available is preposterous. Everyone is different and your studies with 10,000 patients by doctors who are paid in grants and whose funding has been "underwritten in educational disguise" have consistently failed to elucidate the whole picture on any of these meds when used on a given individual. I would be a no see doc if I was one. Donuts for my office staff and samples for my patients, otherwise... well anyways my post below is what Forest's real goal is. If a few suffering people can benefit than great.
>
> Citalopram is the #1 most used AD in the world
>
> Forest has the marketing rights to Citalopram in the US under Celexa, but not in Europe where it actually is the number 1 prescribed antidepressant. In Europe and all other non-us companies, citalopram is owned by various other companies.
>
> Forest will have full international rights to Lexapro and will launch a campaign to convert the entire world on Citalopram (Celexa and other names) to the new improved Leaxapro. Much more marketshare and money.
>
> Believe me when I tell you that there is not a single person in the pharmaceutical industry who cares about you and your depression as much as they care about you and your money. Their motivations are always 100% based on bottom line revenue. Don't ever think for a second they have any other motivation whatsoever. Altruism is not welcome in this industry. Thats what Church on Sunday is for...
>
> Scott
> *** Sorry you feel that way...I am only trying to correct incorrect info givin, and add what I can...Why to you dislike Forest...you certainly dont know Howard Soloman and his story (re: his son). And Forest is definitely not promoting the switching of anybody who's med is working. If a patient is not getting what they want from their med...Lexapro might help. But there is no benefit to the company for changing from Celexa to Lexapro, so why say that? Does it make sense for a company to offer a new/unproved product to the public 3 yrs before the old one expires, or to offer it at a lesser price. I know it might be hard to believe, but Forest actually does have the patients best interests in mind, that is why Lexapro is being offered...it is a better product.
Posted by Anyuser on August 20, 2002, at 14:57:57
In reply to Re: Question re dose, posted by pharmrep on August 20, 2002, at 14:40:38
From Lexapro.com prescribing info: http://www.lexapro.com/prescribing_information/lexapro_pi.pdf, which says, "The recommended dose of Lexapro is 10mg once daily. A fixed dose trial of Lexapro demonstrated the effectiveness of both 10mg and 20mg of Lexapro, but failed to demonstrate a greater benefit of 20mg over 10mg."
Posted by pharmrep on August 20, 2002, at 15:13:03
In reply to Re: Citalopram pharmacology -Dr. Dave » pharmrep, posted by Ritch on August 20, 2002, at 13:10:54
> > NO.....10mg Lex is 40mg of Celexa...trust me.
>
> PharmRep,
>
> I wished somebody would do receptor affinity profiling for r- and s- citalopram separately. If the r- isomer has little affinity for the serotonin reuptake transporter, it (the r-isomer) possibly could have an increased affinity for other receptors involved with side effects. I did find it interesting in the micromedex link posted a while ago that the half-life of s-citalopram is about 22 hrs and that the half-life of s+r-citalopram is about 35 hrs. (If that is inaccurate-please somebody correct me).
>
>
> thanks,
>
> Mitch** hi Mitch...look this one up...it is a study that compares r-citalopram, s-citalopram and celexa (which is both combined). This is proof that Lexapro is more than just 1/2 of Celexa.
c. Sanchez, H. Loft, SA Montgomery Pharmacol Toxicol May 2001; 88(5): 282-286
PS Celexa half-life is 35hrs...Lexapro has a range of 27-32.
Posted by dr. dave on August 20, 2002, at 15:22:46
In reply to Re: Question re dose » pharmrep, posted by Anyuser on August 20, 2002, at 14:57:57
The statement '10mg Lex is 40mg Celexa' doesn't make any sense. Let's get down to the science here - '10mg lex' is 10mg of s-citalopram. '40mg Celexa' is 20mg s-citalopram plus 20mg r-citalopram. That's different. A study has been presented claiming 10mg Lexapro is as effective as 40mg Celexa - but Jack Gorman in his meta-analysis of the research states that this study was too small to demonstrate differences in efficacy. The result of one small trial is not necessarily the complete and absolute truth.
Is the separation expensive? A slow-moving bed plant required to separate stereoisomers costs upward of $5 million. To me, that's expensive.
Where do I get my info? From the published studies, which I have looked through thoroughly, and from a knowledge of pharmacology from studying at Cambridge University.
The studies SUGGEST certain things, but are very very far from demonstrating them conclusively. Statistical significance of difference is inconsistent across the studies. Lexapro will certainly not be cheaper than generic citalopram which is available in Europe to the best of my knowledge.
Although r-citalopram has some affinity to histamine (not 'histomine') receptors this does not mean it is 'inhibiting s-citalopram'. You cannot inhibit a molecule, you can only inhibit a process - which process involving s-citalopram is the r-citalopram/histamine receptor interaction inhibiting?
The whole marketing of this drug seems to be based on sloppy science. I have no problem with Celexa, I prescribe it all over the place, but raising desparate people's hopes with woolly and wishful thinking I object to.
I would be happy to discuss the shortcomings of any particular study on escitalopram that is publically available if we want to get into the science of it.
Posted by pharmrep on August 20, 2002, at 15:38:52
In reply to Re: Question re dose » pharmrep, posted by Anyuser on August 20, 2002, at 14:57:57
Good observation. In week 7 (of 8wk study) 20mg which had showed an edge over 10mg wks 1-6, became = to 10mg. This was due to the tolerabilty of 20 being slighty less than 10, and a few patients dropped out. (this is called last observation carried forward.) All doctors know about this and take LOCF stats in consideration because that is what a real practice is like...if people stop taking their med due to tolerance issues, the "scores" will reflect that. Anyway, to make a long story short(er)...20mg is more effective than 10mg. You can get the full study the FDA had and see for yourself. The graph is clear. (William Burke of Univ. of Nebraska did the study)
Posted by pharmrep on August 20, 2002, at 15:58:42
In reply to Citalopram pharmacology, posted by dr. dave on August 20, 2002, at 15:22:46
> The statement '10mg Lex is 40mg Celexa' doesn't make any sense. Let's get down to the science here - '10mg lex' is 10mg of s-citalopram. '40mg Celexa' is 20mg s-citalopram plus 20mg r-citalopram. That's different. A study has been presented claiming 10mg Lexapro is as effective as 40mg Celexa - but Jack Gorman in his meta-analysis of the research states that this study was too small to demonstrate differences in efficacy. The result of one small trial is not necessarily the complete and absolute truth.
>
> Is the separation expensive? A slow-moving bed plant required to separate stereoisomers costs upward of $5 million. To me, that's expensive.
>
> Where do I get my info? From the published studies, which I have looked through thoroughly, and from a knowledge of pharmacology from studying at Cambridge University.
>
> The studies SUGGEST certain things, but are very very far from demonstrating them conclusively. Statistical significance of difference is inconsistent across the studies. Lexapro will certainly not be cheaper than generic citalopram which is available in Europe to the best of my knowledge.
>
> Although r-citalopram has some affinity to histamine (not 'histomine') receptors this does not mean it is 'inhibiting s-citalopram'. You cannot inhibit a molecule, you can only inhibit a process - which process involving s-citalopram is the r-citalopram/histamine receptor interaction inhibiting?
>
> The whole marketing of this drug seems to be based on sloppy science. I have no problem with Celexa, I prescribe it all over the place, but raising desparate people's hopes with woolly and wishful thinking I object to.
>
> I would be happy to discuss the shortcomings of any particular study on escitalopram that is publically available if we want to get into the science of it.***I agree that the few studies out hardly represent the end-all-be-all of facts, but the 9 out now look promising. Pardon my appreviating...most of my posts I receive are like this, so I do it too. I met Dr. Gorman in June...he spoke for 1 hour and didnt hesitate on the research and efficacy findings. He said Lexapro has greater efficacy. As far as expense of isolating isomers...I dont know what the cost are to Forest...I only know that Lexapro will be less expensive to the patients than Celexa....and there is no generic for Celexa until late 2005 here or Europe. I may have oversimplified my histamine statement, but dont kill me for a typing error. (and it's Forest...not "Forrest")
Forest hasn't even begun any marketing yet, only a few studies are out to show efficacy, side-effect profile, drug to drug interactions, and tolerablity.... The FDA actually encourages isomer science. What dont you like? I would like to cover the studies with you since you have seen them....typing is too hard...what city are you in?
Posted by dr. dave on August 20, 2002, at 16:02:00
In reply to Re: Citalopram pharmacology -Dr. Dave » pharmrep, posted by Ritch on August 20, 2002, at 13:10:54
A study HAS been done on receptor affinity profiling for r- and s-citalopram separately. It is at http://www.cipralex.ch/pdf/poster/sobp_500.pdf
Note that the receptor affinities of r-citalopram are described as 'weak'.
I am reading that Lexapro doesn't cause somnolence - how does this fit with the fact that when study results have been combined, 1.9% of those on placebo complained of somnolence and 6% of those on Lexapro did? This is over three times as common. This gives you an idea of how the facts are being played around with here.
> > NO.....10mg Lex is 40mg of Celexa...trust me.
>
> PharmRep,
>
> I wished somebody would do receptor affinity profiling for r- and s- citalopram separately. If the r- isomer has little affinity for the serotonin reuptake transporter, it (the r-isomer) possibly could have an increased affinity for other receptors involved with side effects. I did find it interesting in the micromedex link posted a while ago that the half-life of s-citalopram is about 22 hrs and that the half-life of s+r-citalopram is about 35 hrs. (If that is inaccurate-please somebody correct me).
>
>
> thanks,
>
> Mitch
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