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Dr. Bob is Robert Hsiung, MD,
bob@dr-bob.orgShown: posts 1 to 8 of 8. This is the beginning of the thread.
Posted by linkadge on May 26, 2007, at 18:32:44
Linkadge
Posted by linkadge on May 26, 2007, at 18:42:58
In reply to Is methylphenidate a 5-ht2b agonist like fenfluram, posted by linkadge on May 26, 2007, at 18:32:44
Or what about abilify? One of abilify's strongest activities is at 5-ht2b.
Linkadge
Posted by Phillipa on May 26, 2007, at 20:07:57
In reply to Re: Is methylphenidate a 5-ht2b agonist like fenfluram, posted by linkadge on May 26, 2007, at 18:42:58
Link I don't understand those articles you post you are so smart. Love Phillipa
Posted by Paulbwell on May 26, 2007, at 23:02:27
In reply to Is methylphenidate a 5-ht2b agonist like fenfluram, posted by linkadge on May 26, 2007, at 18:32:44
"Although binding affinity was not demonstrable at the serotonin (5-HT) transporter site (SERT), novel findings of the study included affinity for the 5-HT1A and 5-HT2B receptor sites for both d- and l-MPH"
This seems to contradict itself,:
-No affinity for 5-ht sites, then
2-Affinity for 5-ht1a, 5ht2b sites.Everythig i'v ever read says Ritalin is a Dopamine and Norphinephrine reuptake inhibitor and a Norph releaser.
Methamphetamine has 5ht releasing properties:
methamphetamine Desoxyn, Methampex, Methedrine, Pervitin, Temmler ADD, ADHD, obesity 10-25mg 10-25 hrs
CYP-2D6 * psychostimulant:
5-HT release +++
NE release +++
DA release ++
DA reuptake inhibition
NE reuptake inhibitionCheers
Posted by Larry Hoover on May 27, 2007, at 8:18:52
In reply to Re: Is methylphenidate a 5-ht2b agonist like fenfluram » linkadge, posted by Paulbwell on May 26, 2007, at 23:02:27
> "Although binding affinity was not demonstrable at the serotonin (5-HT) transporter site (SERT), novel findings of the study included affinity for the 5-HT1A and 5-HT2B receptor sites for both d- and l-MPH"
>
> This seems to contradict itself,:
>
> -No affinity for 5-ht sites, then
> 2-Affinity for 5-ht1a, 5ht2b sites.No affinity for the serotonin transporter (reuptake), but affinity at two specific receptor sites. Unfortunately, they could not discriminate in this assay just what effect the receptor binding had, i.e. agonism or antagonism or in between.
Lar
Posted by linkadge on May 27, 2007, at 8:39:09
In reply to Re: Is methylphenidate a 5-ht2b agonist like fenfluram » Paulbwell, posted by Larry Hoover on May 27, 2007, at 8:18:52
Although, I think the hypothesis (I got from other sites) was that methylphenidate was an agonist. 5-ht2b antagonists tend to increase locomotor activity, wherease 5-ht2b agonists tend to supress it.
What scares me is how the discovery of the cardiac damaging effects of pergolide, and cabergoline completely sliped the radar.
A quote from this article:
http://www.npr.org/templates/story/story.php?storyId=6718704
"And an upcoming study indicates other widely prescribed drugs may cause the same problem."
You see, thats just not cool. I don't know what "other drugs" they are refering to. Ariprazole, for instance, has high binding affinity to 5-ht2b. (althought again, not sure in what manner).And personally, I don't buy the excuse "if they were going to cause problems, we'd know by now", becuase most patients who sustained significant cardiac dammage from permax and cabergoline showed no overt symtpoms.
There are even doctors who suggest discontinuing all many other serotonergically acting medications untill more is known.
Heck, I'd be willing to accept permanant sexual dysfunction before accepting cardiac valve dammage.
Linkadge
Posted by Larry Hoover on May 29, 2007, at 17:57:15
In reply to Re: Is methylphenidate a 5-ht2b agonist like fenfluram » Larry Hoover, posted by linkadge on May 27, 2007, at 8:39:09
> "And an upcoming study indicates other widely prescribed drugs may cause the same problem."
>
>
> You see, thats just not cool. I don't know what "other drugs" they are refering to. Ariprazole, for instance, has high binding affinity to 5-ht2b. (althought again, not sure in what manner).I've got to agree, that's not cool. A quick scan showed high 5-HT2B affinities for ARIPIPRAZOLE CLOZAPINE CYPROHEPTADINE ERGOTAMINE OLANZAPINE
Higher than those of fenfluramine.
I hope they don't dither too much before publishing this new data they anticipate.
> And personally, I don't buy the excuse "if they were going to cause problems, we'd know by now", becuase most patients who sustained significant cardiac dammage from permax and cabergoline showed no overt symtpoms.
:-/
> There are even doctors who suggest discontinuing all many other serotonergically acting medications untill more is known.I think that is an excessive reaction. We know that few serotonergic meds are active at this particular receptor.
> Heck, I'd be willing to accept permanant sexual dysfunction before accepting cardiac valve dammage.
>
> LinkadgeYa, the ticker takes top priority.
Lar
Posted by linkadge on May 30, 2007, at 19:20:05
In reply to Re: Is methylphenidate a 5-ht2b agonist like fenfluram » linkadge, posted by Larry Hoover on May 29, 2007, at 17:57:15
My biggest concern is that SSRI's may be causing the same problems.
We know, for instance, that SSRI's can increase serotonin in the periphery enough to cause GI disturbance / bleeding etc.
I think it is fully possable that altering the level of SERT in the cardiac muscle could activate 5-ht2b sufficantly to cause similar problems.
Again, cabergoline was out before many of the SSRI's wasn't it? So, who's to say "we'd know by now" ?
Linkadge
This is the end of the thread.
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