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Dr. Bob is Robert Hsiung, MD,
bob@dr-bob.orgShown: posts 1 to 10 of 10. This is the beginning of the thread.
Posted by Bob on May 27, 2010, at 23:07:30
Does Seroquel have anticholinergic side effects? It says in the Wikipedia entry that its effects on the acetylcholine system is "controversial".
Posted by SLS on May 28, 2010, at 7:12:16
In reply to Seroquel and AcH?, posted by Bob on May 27, 2010, at 23:07:30
> Does Seroquel have anticholinergic side effects? It says in the Wikipedia entry that its effects on the acetylcholine system is "controversial".
According to one source, quetiapine (Seroquel) produces almost no anticholinergic (muscarinic) receptor binding. However, there was no information regarding norquetiapine, a major active metabolite. I wonder if there is some confusion with the noradrenergic effects of norquetiapine with the effects that are described as being anticholinergic. They might appear similar as they both bias the autonomic system balance in the same direction. It would be good to know what anticholinergic effects are described in the controversy.
- Scott
Posted by Bob on May 28, 2010, at 16:40:44
In reply to Re: Seroquel and AcH?, posted by SLS on May 28, 2010, at 7:12:16
> > Does Seroquel have anticholinergic side effects? It says in the Wikipedia entry that its effects on the acetylcholine system is "controversial".
>
> According to one source, quetiapine (Seroquel) produces almost no anticholinergic (muscarinic) receptor binding. However, there was no information regarding norquetiapine, a major active metabolite. I wonder if there is some confusion with the noradrenergic effects of norquetiapine with the effects that are described as being anticholinergic. They might appear similar as they both bias the autonomic system balance in the same direction. It would be good to know what anticholinergic effects are described in the controversy.
>
>
> - Scott
I saw someone mention dry mouth in another posting, and of course there is the fatigue thing. But I'm not sure what actual effects they were referring to in the article.Bob
Posted by SLS on May 28, 2010, at 17:06:33
In reply to Re: Seroquel and AcH? » SLS, posted by Bob on May 28, 2010, at 16:40:44
> > > Does Seroquel have anticholinergic side effects? It says in the Wikipedia entry that its effects on the acetylcholine system is "controversial".
> >
> > According to one source, quetiapine (Seroquel) produces almost no anticholinergic (muscarinic) receptor binding. However, there was no information regarding norquetiapine, a major active metabolite. I wonder if there is some confusion with the noradrenergic effects of norquetiapine with the effects that are described as being anticholinergic. They might appear similar as they both bias the autonomic system balance in the same direction. It would be good to know what anticholinergic effects are described in the controversy.
> >
> >
> > - Scott
>
>
> I saw someone mention dry mouth in another posting, and of course there is the fatigue thing. But I'm not sure what actual effects they were referring to in the article.Dry mouth (xerostomia) can be a side effect of Strattera (atomoxetine), a selective NE reuptake inhibitor with virtually no anticholinergic activity. It is possible that the dry mouth reported for Seroquel is actually due to the NE reuptake inhibition exhibited by norquetiapine. I doubt Seroquel is anticholinergic.
- Scott
Posted by linkadge on May 28, 2010, at 20:35:29
In reply to Re: Seroquel and AcH?, posted by SLS on May 28, 2010, at 17:06:33
I remember reading somewhere that there was m1 antagonism with seroquel. I will look
Linkadge
Posted by SLS on May 28, 2010, at 22:10:24
In reply to Re: Seroquel and AcH?, posted by linkadge on May 28, 2010, at 20:35:29
> I remember reading somewhere that there was m1 antagonism with seroquel. I will look
Your memory is far better than mine.
- Scott
Posted by SLS on May 28, 2010, at 22:53:39
In reply to Seroquel and AcH?, posted by Bob on May 27, 2010, at 23:07:30
> Does Seroquel have anticholinergic side effects? It says in the Wikipedia entry that its effects on the acetylcholine system is "controversial".
After reviewing the literature I found on Google, I can see why there would be controversy. There are quite a few conflicting reports and opinions. I still think that much of what is described as being anticholinergic with quetiapine is actually noradrenergic.
- Scott
Posted by Bob on May 29, 2010, at 0:06:04
In reply to Re: Seroquel and AcH?, posted by SLS on May 28, 2010, at 22:53:39
> > Does Seroquel have anticholinergic side effects? It says in the Wikipedia entry that its effects on the acetylcholine system is "controversial".
>
> After reviewing the literature I found on Google, I can see why there would be controversy. There are quite a few conflicting reports and opinions. I still think that much of what is described as being anticholinergic with quetiapine is actually noradrenergic.
>
>
> - Scott
That's kinda scary. I thought that at least the scientific community was relatively sure about receptor activity of drugs, at least the receptors we're aware about.
Posted by SLS on May 29, 2010, at 6:03:39
In reply to Re: Seroquel and AcH? » SLS, posted by Bob on May 29, 2010, at 0:06:04
> > > Does Seroquel have anticholinergic side effects? It says in the Wikipedia entry that its effects on the acetylcholine system is "controversial".
> >
> > After reviewing the literature I found on Google, I can see why there would be controversy. There are quite a few conflicting reports and opinions. I still think that much of what is described as being anticholinergic with quetiapine is actually noradrenergic.
> >
> >
> > - Scott
>
>
> That's kinda scary. I thought that at least the scientific community was relatively sure about receptor activity of drugs, at least the receptors we're aware about.One database of ligand affinities to specific receptors reports that Seroquel has some weak to moderate ACh muscarinic M1 binding. However, its potency at this receptor is roughly the same as its potency at D2 and 5-HT2a receptors. This might indicate that at the high dosages used for schizophrenia, some anticholinergic side effects appear. These would be potentiated by norepeneprine reuptake inhibition.
- Scott
Posted by linkadge on May 29, 2010, at 7:46:06
In reply to Re: Seroquel and AcH?, posted by SLS on May 28, 2010, at 22:53:39
According to a PDSP search (enter quetiapine in test ligand)
it says that m1 binding is around 100. These are in the same range as the results for the 5-ht2a receptor. The binding to other muscarinic receptors are lower 500+. The m1 receptor seems to be most implicated in depression however. M1 antagonists are endowed with antidepressant effects. I don't think the m1 receptors control things like mouth watering, sweating or global memory but I could be wrong.
Linkadge
This is the end of the thread.
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