PDF of American Journal of Psychiatry article or
Summary and excerpts from study in the Journals forum of survivingantidepressants
The pretty pictures are from page 4 onwards in the PDF. (Admin note: Pretty pictures here.)
What these fellows did here, was attempt to measure serotonin transporter occupancy at various doses for 5 different drugs. (Zoloft, celexa paxil, effxor and Prozac, not in that order). They fit curves for both the oral doses and blood concentrations.
Long story short for anyone who doesn't know, SSRI’s ‘work’ by binding to the serotonin transporter protein (SERT) and stopping it doing it’s normal thing (reuptake of post-synaptic serotonin), resulting in serotonin hanging around for longer.
Now a couple of interesting things:
-at minimum therapeutic doses in every case, there was about 80% SERT occupancy. That shocked me personally. Even the minimum doses are locking down 80% of your brains reuptake ‘capacity’. Higher doses do more but it’s obviously not linear – they actually have plotted curves, and they’re quite a good fit statistically, particularly for the blood concentrations. Really good in fact.
Point here though is that there’s a long way between 0% at no drug and 80% at the minimum dose.
-the curves man, look at the curves. This gives a fairly good indication of why some people find tapering necessary. You NEED a percentage taper just to get a linear decrease in SERT occupancy. Linear decreases in dose will actually hit you with exponentially increasing drops in SERT occupancy, particularly drops between the minimum therapeutic dose and 0
Basically, this paper provides a real basis for percentage reductions in dose when discontinuing SSRI’s.
I realize I'm kinda preaching to the converted and telling people what they already know, but it seems there may actually be a real reason why some people find it necessary to do these percentage tapers to get off SSRI's.
Caveat: I have no idea what the relationship between SERT occupancy and post synaptic serotonin is, it’s probably not linear since if it was higher doses would have basically no effect, but this is nevertheless very interesting to look at.
They were only looking at one part of the brain but pointed out it correlated strongly to elsewhere.
To search for whether there is a study for your medication, google the generic name of the drug with these other two search terms: 5HTT occupancy
If you find a paper, please post the both the name of the medication and a link to the paper.
2016-July-01, Cymbalta (duloxetine)
2016-November-12, Anafranil (clomipramine) and Luvox (fluvoxamine)
Link to study on occupancy vs. dose
Link to chart of occupancy-dose relationship
Edited by scallywag, 12 November 2016 - 12:29 PM.
add Anafranil and Luvox study