Posted by chemist on July 13, 2004, at 8:22:48
In reply to Re: Ooops, Seroquel doesn't block M1 » chemist, posted by Sad Panda on July 13, 2004, at 3:53:34
> > > > > Got a burning question for you Panda. After my recent bad experience with Seroquel, I have to agree with you. AP's are a bit overkill if all one wants is to get some sleep, and who knows what else is brewing in the chemical soup. I'm very curious as to my extreme and immediate reaction. Very difficult waking up, much like when I was taking trazodone. I felt quite depressed and out of it the 4 days I was on 6.25 or 12.5 pm. Very lethargic but jittery at the same time.
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> > > > > My first thought was 'oh, I'm having a bad reaction to a reduction of dopamine - I need that dopamine'. Now, I realize that AP's reduce dopamine as part of their antipsychotic action, but I was under the impression Seroquel was not a heavy dopamine hitter. Also, none of these meds change neurotransmitter/receptor functionality that quickly, so dopamine doesn't seem a likely candidate. So perhaps the path is a similar 5Ht2-a blockade as w/trazodone and remeron, but we're still talking serotonin receptors and there's a lag time. It doesn't happen that quickly. My question is, is there also a histamine release which could account for the groggyness? Might this tie in with a possible dysfunction in my histamine levels? I haven't been tested for any of this but have been following the histadine/methylation theories. I'm also taking lithium and St. John's Wort (which is working surprisingly well). What could be at the root of the severe depression and restlessness I experienced immediately from Seroquel? After not taking it last night, I woke this morning fresh as a daisy and feeling sooooo much better. - Barbara
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> > > > Seroquel block Alpha-1 NE receptors the most, so I would possibly blame that. Coming in a close second is it's H1 blockade. At low doses I would say that's all it does as the next receptor is blocks is actually M1, so you'd probably notice a little dry mouth & constipation before 5-HT2A & D2 blockade ever comes to the party.
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> > > > On this page is a pretty good table showing the differences: http://www.vh.org/adult/provider/psychiatry/CPS/04.html#table2
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> > > > Cheers,
> > > > Panda.
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> > > Ooops, Ignore what I said about Seroquel probably causing antimuscarinic dry mouth & constipation. Most other websites say it doesn't block M1.
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> > > Cheers,
> > > Panda.
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> > panda, i'm not letting you off the hook so easily, having recently pronounced you the expert. my PDR white-sheet from astrazeneca says ``no appreciable affinity at cholinergic muscarinic and benzodiazepine receptors (IC_{50s} > 5000 nM).'' given an IC_{50} for D_{1} at 1268 nM and IC_{50} of 329 nM for D_{2}, what's an order of magnitude or two among friends? you're still in charge...... :) all the best, chemist
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> Hi Chemist,
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> Looks like I am half-wrong or half-right, Seroquel's monograph says it has no affinity for muscarinic receptors, yet constipation is high on the list of side effects straight after dry mouth. I know Alpha-1 blockade produces dry mouth, but what causes constipation beside M1 blockade?
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> Cheers,
> Panda.
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hey panda the only thing i can think of would implicate smooth muscle. this would involve adenosine (and the ATP cycle) in some way, although i can't seem to get from ``here to there.'' i think we need to call larry hoover in on this one......all the best, chemist
poster:chemist
thread:339744
URL: http://www.dr-bob.org/babble/20040712/msgs/365589.html