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Dr. Bob is Robert Hsiung, MD,
[email protected]Shown: posts 1 to 4 of 4. This is the beginning of the thread.
Posted by AndrewB on January 5, 2001, at 5:58:19
Are there any drug interactions or other things to worry about when combining pindolol and buspirone with Zyprexa or amisulpride. Will buspirone's D2 antagonism blunt the action of these neuroleptics?
Ziprasidone's effectiveness and better side effect profile when compared to Zyprexa is speculated to be due to its action as a strong 5-HT1A agonist. When taken in low doses pindolol is a 5-HT1A presynaptic autoreceptor antagonist, thus complementing the moderate 5-HT1A postsynapitc receptor agonist action of buspirone.
Note: At low doses Zyprexa is a D2 autorector antagonist and 5-HT2 receptor antagonist, amisulpride is a D2/D3 autoreceptor antagonist, and Ziprasidone is a D2 autoreceptor antagonist, 5-HT2 antagonist and 5-HT1A agonist.
Thanks for any help,
AndrewB
Posted by JahL on January 5, 2001, at 14:38:54
In reply to Is Pindolol+Busirone+ a neuroleptic safe?, posted by AndrewB on January 5, 2001, at 5:58:19
> Are there any drug interactions or other things to worry about when combining pindolol and buspirone with Zyprexa or amisulpride. Will buspirone's D2 antagonism blunt the action of these neuroleptics?
Hi Andrew.
I took Sulpiride (200mg/D) + Buspirone (30mg/D) + Pindolol (10mg/D) for a month without any apparent side-effects/problems.
Jah.
Posted by anita on January 5, 2001, at 23:07:12
In reply to Is Pindolol+Busirone+ a neuroleptic safe?, posted by AndrewB on January 5, 2001, at 5:58:19
Andrew,
I believe the combo would be "safe," but I don't know if buspirone's D2 antagonism would be high enough to offset the low-dose neuroleptic D2 actions. Sorry, am rusty on buspirone.
Can you please tell me where you saw that low-dose Zyprexa is a D2 autoreceptor antagonist? I have been looking for this info for ages. Do you know if low-dose risperidone is as well?
Thanks,
anita
> Are there any drug interactions or other things to worry about when combining pindolol and buspirone with Zyprexa or amisulpride. Will buspirone's D2 antagonism blunt the action of these neuroleptics?
>
> Ziprasidone's effectiveness and better side effect profile when compared to Zyprexa is speculated to be due to its action as a strong 5-HT1A agonist. When taken in low doses pindolol is a 5-HT1A presynaptic autoreceptor antagonist, thus complementing the moderate 5-HT1A postsynapitc receptor agonist action of buspirone.
>
> Note: At low doses Zyprexa is a D2 autorector antagonist and 5-HT2 receptor antagonist, amisulpride is a D2/D3 autoreceptor antagonist, and Ziprasidone is a D2 autoreceptor antagonist, 5-HT2 antagonist and 5-HT1A agonist.
>
> Thanks for any help,
>
> AndrewB
Posted by SLS on January 6, 2001, at 9:04:24
In reply to Re: Pindolol+Busirone+neuroleptic safe? For Andrew, posted by anita on January 5, 2001, at 23:07:12
> Can you please tell me where you saw that low-dose Zyprexa is a D2 autoreceptor antagonist? I have been looking for this info for ages. Do you know if low-dose risperidone is as well?
From the bowels of my mind, I seem to have vague memories of things that I can't verify right now. I think most, if not all neuroleptic D2 receptor antagonists block both presynaptic and postsynaptic receptors simultaneously. The differences seem to lie in their relative affinities for both types of receptor. I believe they have variances in specific domains. In addition, D2 receptors exist in low-affinity and high-affinity states. Sulpiride and amisulpride are considered "preferential" for D2 presynaptic autoreceptors relative to postsynaptic D2 receptors; it binds more tightly to pre- than post-. The molecular configurations (conformations?) of presynaptic and postsynaptic receptors are generally different enough to actually differ in their affinities for endogenous dopamine and other ligands. Presynaptic autoreceptors are of significantly higher affinity, or more generally in the high-affinity state. Therefore, some D2 ligands will bind more tightly and occupy first presynaptic autoreceptors as the concentration increases where the number of postsynaptic receptors blocked becomes clinically significant. My guess is that some ligands actually cause the receptor to change conformations from one state to the other. Perhaps amisulpride switches and locks presynaptic autoreceptors into their high-level affinity state, making them less likely to be displaced by dopamine while being incapable of switching and locking the molecularly different postsynaptic receptors. My guess is that nonpreferential neuroleptics with low binding affinities to D2 receptors (Risperdal and Zyprexa) would foster a greater pre/post ratio of antagonism at low dosages, thus producing enhanced dopaminergic transmission in limbic and and other structures involved with mood (Anita knows better what structures are involved).
- Scott
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Dr. Bob is Robert Hsiung, MD,
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