![[dr. bob]](/dr-bob-sm.gif)
Dr. Bob is Robert Hsiung, MD,
bob@dr-bob.orgShown: posts 1 to 3 of 3. This is the beginning of the thread.
Posted by anita on November 8, 2000, at 19:36:52
Hi,
I'd like to know if very low doses of risperidone or Zyprexa increase dopamine globally, not just in the mesocortical pathway via 5HT2A antagonism. In other words, do low doses of these meds work like amisulpride, which increases dopamine globally at low doses? For various reasons, it's very important that I try to find an answer to this question, so any input would be greatly appreciated.
I am taking a low dose of risperidone (1mg/day) and it feels a lot like low-dose amisulpride.
anita
Posted by SLS on November 8, 2000, at 21:08:32
In reply to Q. re atypical antipsychotics and dopamine -- Cam?, posted by anita on November 8, 2000, at 19:36:52
Meee 2
Anita, of the "atypicals", Risperdal has the *lowest* ratio of 5-HT2/DA2 receptor blockade. Risperdal also increases prolactin levels more than the other atypicals. Of the atypicals, Risperdal is the most like Haldol, and has the greatest potential to cause EPS. Zyprexa, on the other hand, has a very high 5-HT2/DA2 ratio. Perhaps Zyprexa has a low-dose DA-enhancing window that is more favorable than Risperdal. Of course, there is plenty of literature indicating that Risperdal works well to augment antidepressants. I have no way of knowing, but I have been hoping that these drugs act like amisulpride in this regard. Yooo 2? :-)
> Hi,
>
> I'd like to know if very low doses of risperidone or Zyprexa increase dopamine globally, not just in the mesocortical pathway via 5HT2A antagonism. In other words, do low doses of these meds work like amisulpride, which increases dopamine globally at low doses? For various reasons, it's very important that I try to find an answer to this question, so any input would be greatly appreciated.
>
> I am taking a low dose of risperidone (1mg/day) and it feels a lot like low-dose amisulpride.
>
> anita
Posted by JohnL on November 9, 2000, at 3:56:28
In reply to Q. re atypical antipsychotics and dopamine -- Cam?, posted by anita on November 8, 2000, at 19:36:52
> Hi,
>
> I'd like to know if very low doses of risperidone or Zyprexa increase dopamine globally, not just in the mesocortical pathway via 5HT2A antagonism. In other words, do low doses of these meds work like amisulpride, which increases dopamine globally at low doses? For various reasons, it's very important that I try to find an answer to this question, so any input would be greatly appreciated.
>
> I am taking a low dose of risperidone (1mg/day) and it feels a lot like low-dose amisulpride.
>
> anitaAnita,
It's very hard to compare these APs because literature I've seen doesn't provide specific information on dopamine blockade. In the case of Amisulpride, good information is available. It blocks D2 receptors presynaptically at low doses to enhance dopamine transmission. At higher doses it also blocks D2 receptors postsynaptically to reduce dopamine. So a whole spectrum of desired results can be achieved depending on the dosage level.With Zyprexa and Risperdal, it is stated they both block D2 receptors. But it doesn't state anywhere I've seen whether that blockade is presynaptic, postsynaptic, or both. I would love to know, but have found the search for this information frustrating.
In addition to D2 blockade, they also block other receptors such as 5HT2, alpha2 adrenergic, and histimine, in varying degrees. Amisulpride doesn't. It acts only on dopamine. I've often thought that taking Zyprexa is somewhat similar to taking a combination of Amisulpride+Remeron. Except I find the histimine effect of Zyprexa far stronger and longer lasting than Remeron, and thus the heavy sedation I experienced with Zyprexa.
Like you, I have a lot of questions about these drugs. It's hard to find the answers. All I know for sure is that Amisulpride, for whatever reason, gets rid of my anhedonia symptoms. Zyprexa does too. Risperdal does too. (all in low doses) But of them all, Amisulpride was superior for me. It seemed like it was 'cleaner' than the others, and didn't counteract the good effects with heavy side effects. Zyprexa for example had far too many side effects for me. Risperdal was a bit easier to handle. Amisulpride was the easiest of all to handle, and oddly also the most effective. Why and how, dunno.
John
This is the end of the thread.
Psycho-Babble Medication | Extras | FAQ
Dr. Bob is Robert Hsiung, MD,
bob@dr-bob.org
Script revised: February 4, 2008
URL: http://www.dr-bob.org/cgi-bin/pb/mget.pl
Copyright 2006-17 Robert Hsiung.
Owned and operated by Dr. Bob LLC and not the University of Chicago.