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Dr. Bob is Robert Hsiung, MD,
bob@dr-bob.orgShown: posts 1 to 9 of 9. This is the beginning of the thread.
Posted by jms600 on February 15, 2008, at 16:36:48
I have been reading on the net that Seroquel is a serotonin antagonist. Can, therefore, Seroquel interfere with the action of antidepressants such as the SSRIs??
Posted by dbc on February 15, 2008, at 17:58:29
In reply to Seroquel - is it a serotonin antagonist?, posted by jms600 on February 15, 2008, at 16:36:48
As far as i know they dont do any sort of magic to the axion which is what makes SSRIs work. Simply dumping more serotonin into the neuronal cleft doesnt make an AD work. All Atypical antipsychotics more or less just manipulate the 5ht-2a receptor to cause dopamine levels to drop. The only current one that displays some weird anti-depressant side effect is abilify but no one is sure why.
Posted by Phillipa on February 15, 2008, at 19:44:36
In reply to Re: Seroquel - is it a serotonin antagonist?, posted by dbc on February 15, 2008, at 17:58:29
Pdoc said it is now approved for mood stabalization. Not true or true? Love Phillipa
Posted by dbc on February 15, 2008, at 21:29:36
In reply to Re: Seroquel - is it a serotonin antagonist? » dbc, posted by Phillipa on February 15, 2008, at 19:44:36
Seroquel or abilify? If you mean seroquel i wouldnt be suprised because its being used off label for everything these days on the level gabapentin was. I does have some anxiolytic qualities because of its histamine action.
If you mean abilify again im not terribly suprised because it seems to have some unique qualities other anti-psychotics dont. But it worries me if they're using it all willy nilly because theres been some psychotic reactions to it which is why i chickened out on trying to use it for depression.
Posted by Phillipa on February 15, 2008, at 23:46:38
In reply to Re: Seroquel - is it a serotonin antagonist?, posted by dbc on February 15, 2008, at 21:29:36
I know my pdocs scare me they often believe what is told by drug reps and just don't know themselves she said abilify. Not going there. And seroquel head fell in my lap at 12.5mg. Love Phillipa
Posted by Darwin on February 17, 2008, at 14:19:35
In reply to Re: Seroquel - is it a serotonin antagonist?, posted by dbc on February 15, 2008, at 17:58:29
Seroquel and several other AP's also have antidepressant effects.
Posted by bleauberry on February 18, 2008, at 20:15:04
In reply to Seroquel - is it a serotonin antagonist?, posted by jms600 on February 15, 2008, at 16:36:48
It's complicated to try to explain, and frankly even the most educated explanation of any human falls short of how complicated the brain is. But very basically, the blockage of those receptors can do two things. It can stimulate the release of more neurotransmitters, and it can mute the effects of those extra neurotransmitters at the receptors that cause side effects, but not so much at the receptors are desired for mood improvement. More potential antidepressant action while minimizing side effects of other drugs at the same time.
Antipsychotics are often used to augment antidepressants. The more common ones I've seen in literature and here are prozac plus zyprexa, lexapro plus risperdal, and effexor plus risperdal. Seroquel is used probably more than any of the others for insomnia, but at higher doses can add some antidepressant augmentation as well.
Mileage varies. One person will feel better. Another will get akathisia or sedation. Another will feel worse. Despite all the theory we try to explain, the only true test is to take the doses and see what happens.
> I have been reading on the net that Seroquel is a serotonin antagonist. Can, therefore, Seroquel interfere with the action of antidepressants such as the SSRIs??
Posted by yxibow on February 20, 2008, at 6:36:56
In reply to Seroquel - is it a serotonin antagonist?, posted by jms600 on February 15, 2008, at 16:36:48
> I have been reading on the net that Seroquel is a serotonin antagonist. Can, therefore, Seroquel interfere with the action of antidepressants such as the SSRIs??
Not particularly, for a variety of reasons in fact they can improve the action especially in patients with OCD.
But they work differently -- Seroquel is a blockade of multiple 5HT transmitters like Trazodone and a few other agents while SSRIs work a bit differently on the reuptake of serotonin.
Now massive amounts of all sorts of serotonin agents of course isn't the best idea and the doctor should be skilled in giving appropriate doses to avoid serotonin syndrome but in general, for example I have taken in the past 450 Luvox with 400 mg of Seroquel. As they say, your miles may vary.
Posted by Dopamine123 on February 21, 2008, at 14:01:14
In reply to Re: Seroquel - is it a serotonin antagonist?, posted by bleauberry on February 18, 2008, at 20:15:04
http://www.neurotransmitter.net/drug_reference.html
"Quetiapine (seroquel) is an antagonist at serotonin 5-HT2A receptors (119). It is also a low potency dopamine D2 receptor inverse agonist (106). Quetiapine is an antagonist at alpha-1A-adrenoceptors (25), alpha-1B-adrenoceptors (25), and alpha-2C-adrenoceptors (40). In addition, the drug is a histamine H1 receptor antagonist (27)."
http://www.preskorn.com/columns/0003.html
"Based on its binding profile, some psychiatrists have used mirtazapine both to augment the antidepressant effects of serotonin uptake inhibitors (i.e., SSRIs and low dose venlafaxine) and to treat their adverse effects. To put this discussion in perspective, a few comments about the effects of SSRIs and venlafaxine may be helpful. These antidepressants are believed to work by increasing serotonin availability to the various serotonin receptors in the brain by slowing the neuronal reuptake of serotonin after its release. Thus, these drugs work as indirect serotonin receptor agonists. While SSRIs are "selective" in terms of directly affecting only the serotonin uptake pump, they are not "selective" in terms of their agonism of serotonin receptors. They increase serotonin availability to all serotonin receptors. Agonism of the 5-HT1A receptor is currently believed to be the mechanism mediating the antidepressant efficacy of these drugs. Conversely, agonism of the 5-HT2A, 5HT2C, and 5-HT3 receptors may principally mediate the adverse effects of these drugs: sleep disturbance, anxiety and weight gain, and nausea/loose stools/vomiting, respectively.7"
Seroquel antagonizes the 5-ht2a receptor which can reduce side effects and increase the antidepressant effect of SSRI's. By antagonizing the 5-ht2a receptor there is more serotonin available to activate the 5-ht1a receptor which is thought to mediate antidepressant efficacy.
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