Posted by ed_uk2010 on July 4, 2010, at 8:20:34
In reply to Re: what is 50mg anafranil = to as SSRI ?, posted by SLS on July 3, 2010, at 19:32:59
>Potency as an SRI given as tissue concentration is not the same as therapeutic efficacy given as dosage.
Definitely, but no one is suggesting that.
What the PET studies show is that citalopram, escitalopram, fluoxetine, paroxetine, sertraline, duloxetine and venlafaxine all demonstrate approximately 80% SERT occupancy at the minimum doses which have been demonstrated to be effective in clinical trials. These are the doses which I listed in my post above. Higher doses produce slightly greater occupancy but the difference is not large.
Clomipramine is different because although 10-20mg per day is now believed to produce approximately 80% SERT occupancy in the 'average patient', such low doses have not been proven to be effective in clinical trials. One of the reasons for this could be that very low doses of clomipramine do not appear to have been studied - all trials used higher doses.
Unlike SSRIs, which have a relatively flat dose-response curve at usual doses, I would expect clomipramine to show increased efficacy at high doses because it produces many other effects apart from SERT inhibition. Even so, I do think it's very likely that 20mg clomipramine would be more effective than placebo as an antidepressant.
poster:ed_uk2010
thread:952518
URL: http://www.dr-bob.org/babble/20100628/msgs/953221.html