Posted by Sunnely on October 26, 2001, at 22:42:31
In reply to What's new about the new Celexa?, posted by daveman on October 25, 2001, at 22:22:47
> Okay, I've been reading about this "new" Celexa for awhile now. But I've yet to figure out what's so "new". As I've been stable on plain old Celexa for almost a year, I'm curious to learn what the "new" version offers. Thanks for any responses.
>
> Dave**************************************************
S-Citalopram
Many biologically active compounds are made up of racemic mixtures. The selective serotonin reuptake inhibitor (SSRI) citalopram (Celexa) is a mixture of an S and an R enantiomer. The reuptake inhibitory activities of citalopram appear to reside in the S enantiomer, making S-citalopram a highly selective SSRI, with no effect on catecholamine reuptake. S-citalopram is active in animal models of antidepressant activity, and in vitro studies suggest it has low likelihood of pharmacokinetic drug interactions.
A study of almost 500 outpatients with major depression compared two doses of S-citalopram, 10 mg/day and 20 mg/day; racemic citalopram (Celexa), 40 mg/day; and placebo in an 8-week, double-blind, random-assignment protocol. Both doses of S-citalopram were greater in efficacy than placebo, with a suggestion of higher efficacy with the 20 mg/day dose than at 10 mg/day. Racemic citalopram was also statistically superior to placebo in efficacy, but S-citalopram at both doses produced greater mean changes than citalopram in key outcome measures at endpoint.
The 10 mg/day dose of S-citalopram was better tolerated than citalopram, 40 mg/day. The rates of discontinuation due to adverse events were 10.4% for S-citalopram, 20 mg/day; 8.8% for citalopram; 4.2% for S-citalopram, 10 mg/day; and 2.5% for placebo. The frequency of treatment-emergent adverse events was only slightly higher for patients in the S-citalopram 10 mg/day group versus patients in the placebo group (79.0% versus 70.5%, P = NS), and comparable between S-citalopram, 20 mg/day, and citalopram, 40 mg/day (85.6% versus 86.4%). The most common adverse events in the active treatment groups were nausea, diarrhea, insomnia, and dry mouth.
In an analysis of three studies with over 1300 subjects, the main adverse event showing the difference between S-citalopram, 10 to 20 mg/day and placebo was insomnia, which occurred at incidences of 9% and 4%, respectively.
Data from these trials suggest GREATER and FASTER symptomatic improvement in depression among patients treated with S-citalopram than with citalopram. There is also a suggestion that S-citalopram is faster in reducing anxiety symptoms in depression than citalopram and that the higher dose of S-citalopram will reduce anxiety to a greater degree.
As occurred with the Prozac brand of fluoxetine, the Celexa brand of citalopram will soon lose patent protection. Patenting an enantiomer gives the manufacturer an opportunity to profit from patent protection for a much longer period. R-fluoxetine was believed to be the clinically active enantiomer of fluoxetine, but hopes for its reaching market were dashed when problems developed, possibly related to an adverse event.
We should know before long whether S-citalopram will come to market in the U.S. and other countries. If so, it is likely to be priced comparably to other new antidepressants but much higher than the generic racemic citalopram. Will the cost be worth it, and how will S-citalopram compare to other antidepressants? Will S-citalopram at doses sufficient to optimize efficacy be more tolerable than generic citalopram? The science is interesting, but the clinical implications and health care economics will undoubtedly gain greater attention. We eagerly await more information.
From: Biological Therapies in Psychiatry, Alan J. Gelenberg, M.D., August 2001.
P.S. I've heard once S-citalopram labeled as the "Super" Celexa. We'll find out soon if it lives up to this billing.
poster:Sunnely
thread:82129
URL: http://www.dr-bob.org/babble/20011025/msgs/82416.html