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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 Betternow on January 22, 2004, at 22:15:30
Are SSRI sexual side effects mediated through 5ht2a agonism?
If so would Geodon as a ssri and a 5ht2a antagonist be efficacious without the sexual side effects?
Posted by Questionmark on January 23, 2004, at 1:44:45
In reply to Geodon experiences and specifically sexual side fx, posted by Betternow on January 22, 2004, at 22:15:30
> Are SSRI sexual side effects mediated through 5ht2a agonism?
Yes, it's believed to be primarily caused by 5-ht2a agonism.
> If so would Geodon as a ssri and a 5ht2a antagonist be efficacious without the sexual side effects?Wow, does it have those properties? i would assume the answer to your question to be "yes" then. Do you happen to know all of Geodon's neuropharmacology/ receptor activities? i would love to know this-- for all the atypicals actually. But if there is significant NE, or especially, dopamine receptor antagonism, it might not be that good an antidepressant. Also alot of times 5-ht2a antagonism seems to counteract the beneficial effects of SRIs. So i'm not sure.
Posted by Betternow on January 23, 2004, at 18:58:29
In reply to Re: Geodon ..., posted by Questionmark on January 23, 2004, at 1:44:45
It does antagonize D2 and D3, inbits uptake of seratonin and NE.
Can any users comment on their experience. I wonder if one combined SSRI with small amount of Geodon, would sexual side effects diminish due to 5ht2a antagonism-Just trying to think outside the box.
CLINICAL PHARMACOLOGY
Pharmacodynamics
Ziprasidone exhibited high in vitro binding affinity for the dopamine D 2 and D 3 , the serotonin 5HT 2A , 5HT 2C , 5HT 1A , 5HT 1D , and (alpha) 1 -adrenergic receptors (K i 's of 4.8, 7.2, 0.4, 1.3, 3.4, 2, and 10 nM, respectively), and moderate affinity for the histamine H 1 receptor (K i =47 nM). Ziprasidone functioned as an antagonist at the D 2 , 5HT 2A , and 5HT 1D receptors, and as an agonist at the 5HT 1A receptor. Ziprasidone inhibited synaptic reuptake of serotonin and norepinephrine. No appreciable affinity was exhibited for other receptor/binding sites tested, including the cholinergic muscarinic receptor (IC 50 >1 µM).The mechanism of action of ziprasidone, as with other drugs having efficacy in schizophrenia, is unknown. However, it has been proposed that this drug's efficacy in schizophrenia is mediated through a combination of dopamine type 2 (D 2 ) and serotonin type 2 (5HT 2 ) antagonism. Antagonism at receptors other than dopamine and 5HT 2 with similar receptor affinities may explain some of the other therapeutic and side effects of ziprasidone.
Ziprasidone's antagonism of histamine H 1 receptors may explain the somnolence observed with this drug.
Ziprasidone's antagonism of (alpha) 1 -adrenergic receptors may explain the orthostatic hypotension observed with this drug.
This is the end of the thread.
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Dr. Bob is Robert Hsiung, MD,
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