Posted by dr. dave on November 1, 2002, at 7:11:50
In reply to Re: Citalopram pharmacology » dr. dave, posted by SLS on October 31, 2002, at 19:57:13
Dear Scott,
> > The main point I've been trying to make on this board is that claims are being made on very weak evidence about this drug,
>
> I haven't been following the posts closely enough. What are the claims being made? What evidence has been offered to cooraborate these claims? Thanks.
The basic claim is that it is significantly different from Celexa in terms of side-effects and efficacy. I'm not sure there's been any particular evidence cited to support the idea that it has fewer side-effects, it's just one of those things that is claimed and then gets repeated and repeated. The evidence from the three trials from the initial development programme that Forest and Lundbeck ran clearly show there is no significant difference. I've quoted the figures in a previous post.In terms of efficacy, the main evidence cited is a meta-analysis of the three initial trials that compared citalopram and escitalopram. On the outcome measure that was defined at the outset of the trials, there was no significant difference. By analysing the data differently they have come up with some results which show a marginal but statistically significant difference in favour of escitalopram. I am highly skeptical of the clinical significance of this result, given that it is in the context of so many other results which show no difference, and the small magnitude of the difference.
> How would you critique my hypothesis regarding antagonistic stereochemisty between the enantiomers? How might this relationship be viewed with respect to the actions of partial agonists at neurotransmitter receptors?The affinity of r-citalopram for the serotonin re-uptake transporter is much much less than that of s-citalopram, by an order of about thirty times. There is therefore little chance of significant competition. The r-citalopram molecules have just too weak an affinity for the transporter to stop the s-citalopram molecules muscling in.
> > I feel qualified to comment on the science as it's what I've been educated in for many years, and it's my job to have an understanding of it - but I'm only commenting, which is not to say I don't get things wrong sometimes.
>
> What is your background, and how are you applying it today?
>
I studied natural sciences and medical science at Cambridge University in the UK, and I'm now a practicing psychiatrist.David
poster:dr. dave
thread:109458
URL: http://www.dr-bob.org/babble/20021101/msgs/126050.html