Posted by Questionmark on November 30, 2007, at 2:22:45
In reply to Re: Prozac in particular, posted by circusboy on November 15, 2007, at 11:18:06
Ok no the metabolite of fluoxetine is *not* duloxetine but norfluoxetine, as you said. And it appears that norfluoxetine is an SSRI as well, from what info i could find on it. I don't know where i ever got that it was duloxetine or that either was a selective NRI. I'm an IDiot. Sorry.
Oh but norfluoxetine does have a very long half-life. i was right about that at least.
That's interesting that atomoxetine binds to the kappa opioid receptor. I still don't think that's the primary reason, if at all, for its dysphoric qualities though. That's also apparently common with reboxetine (unless it has a kappa effect too), and i had similar feelings on Parnate, which has strong catecholaminergic properties.
> > Yeah, Prozac acts on the 5-HT2C receptor (as well), i'm pretty sure. But remember part of what could contribute to its anxiogenic and more or less stimulating type of effects is that its metabolite... duloxetine, i believe (as opposed to Prozac/fluoxetine)... is a NRI-- and one with a significantly long half-life, if i'm not mistaken.
> Duloxetine is Cybalta, right? The only major fluoxetine metabolite I know about is norfluoxetine... I hadn't heard that it was extra-sticky at the NE transporter. That's interesting.
> > Also, do you know, does it pretty much sound like overall consensus here that Zoloft does have qualities different enough than other SSRIs in a way that feels like a dopamine reuptake inhibiting effect? That would be interesting because, yeah, the experts seem to think that its effect on the DA transporter would be negligible in terms of subjective effects.
> I don't know if it's the consensus here, really. My comments along those lines are as much hope as fact. :) I remember sertraline feeling subjectively (in retrospect) dopaminergic when I took it 10 years ago... we'll see what it does for me this time. So far (less than 1 week at 25mg) it's MUCH better in the motivation/concentration/energy department than Lexapro (the last SSRI I took, 6 months ago) was. Either that or I'm getting a healthy placebo effect.
> > Also, does Strattera really act on the kappa opioid receptor? I never heard that. That's really interesting if so.
> Yep. Search pubmed for "atomoxetine kappa opioid" and it'll pop right up. (I recalled incorrectly -- it's actually an atomoxetine metabolite that has this action). Seems at least a possible mechanism for the crushing dysphoria Strattera caused in me and others. It also makes sense that it would be a metabolite, since the bad feelings didn't kick in for several days.