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Dr. Bob is Robert Hsiung, MD,
bob@dr-bob.orgShown: posts 1 to 14 of 14. This is the beginning of the thread.
Posted by Katgirl on April 6, 2010, at 17:33:05
Hi all you super smart med "techies"! A new medication has finished up trials, and I'm hoping it may be out next year. It is identified as LU AA21004 and is a 5-HT3 antagonist and 5-HT1A partial agonist. Can you tell from that how it would be different from, say an SSRI (which I can no longer tolerate). Or what kind of side effects it might or might not have? Or just any insight of how it would work, would be appreciated. Thanks! Katgirl (who is still white knuckling it through life without a medication)
Posted by Phillipa on April 6, 2010, at 17:33:05
In reply to Technical question on new anti-depressant, posted by Katgirl on April 5, 2010, at 10:14:43
Katgirl I don't know but wanted you to know I admire your strength . What is your diagnosis and what meds have you tried. And right now your're med free? Phillipa
Posted by tensor on April 6, 2010, at 17:33:05
In reply to Technical question on new anti-depressant, posted by Katgirl on April 5, 2010, at 10:14:43
Hi,
I know mirtazapine possesses 5HT3 antagonist action and as far as I know it helps with nausea or other gastrointestinal problems.
Buspirone is a 5HT1A partial agonist, the theory behind such drugs is that they allow repletion of serotonin in neurons. If an SSRI is used but the the neurons are depleted then the SSRI would have no effect since there is no serotonin around anyway. Thus, adding a 5HT1A partial agonist could in theory make an SSRI effective and/or more effective./Mattias
> Hi all you super smart med "techies"! A new medication has finished up trials, and I'm hoping it may be out next year. It is identified as LU AA21004 and is a 5-HT3 antagonist and 5-HT1A partial agonist. Can you tell from that how it would be different from, say an SSRI (which I can no longer tolerate). Or what kind of side effects it might or might not have? Or just any insight of how it would work, would be appreciated. Thanks! Katgirl (who is still white knuckling it through life without a medication)
Posted by linkadge on April 6, 2010, at 17:33:05
In reply to Re: Technical question on new anti-depressant » Katgirl, posted by Phillipa on April 5, 2010, at 12:25:52
Well, 5-ht3 antagonists have anti anxiety and anti-nausiant effects. The 5-ht3 receptors control the release of glutamate throughout the brain.
One theory is that SSRI's work indirectly by desensitizing the 5-ht3 receptors and hence inhibiting the release of glutamate in the brain. 5-ht3 antagonists would mimic this effect, potentially without effects on other serotonin receptors.
Similarly, 5-ht1a agonists have antidepressant and antianxiety properties. They may be more effective for anxiety, and possibly more effective in women. 5-ht1a agonists also decrease limbic glutamate neurotransmission.
Together, I would speculate that this agent might have more antianxiety (and possible mood stabilizing) effects than antidepressant effects, but who knows.
Because its actions appear to be specific to certain serotonin receptors it would theoretically cause less nausia, insomnia, anxiety, activation or apathy.
It might also be useful as an SSRI adjunct to reduce nausia and/or anxiety associated with SSRIs.
Linkadge
Posted by ed_uk2010 on April 6, 2010, at 17:33:05
In reply to Technical question on new anti-depressant, posted by Katgirl on April 5, 2010, at 10:14:43
It sounds like a treatment for generalised anxiety. A bit like a cleaned up version of buspirone.
Posted by desolationrower on April 6, 2010, at 17:33:06
In reply to Re: Technical question on new anti-depressant, posted by linkadge on April 5, 2010, at 12:52:07
I woudl say the actual effects might depend on just how strong the partial agonism is at 5ht1a (closer to agonist or closer to antagonist). there are a number of drugs that are ht3 antagonists; i would think the side effects might be lower than typical.
-d/r
Posted by Katgirl on April 6, 2010, at 17:33:41
In reply to , posted by on December 31, 1969, at 18:00:00
Thanks for the insight everyone! Actually, stomach upset/nausea is a major issue for me with SSRI's, so this is very good news. According to the information I have the drug was in trials for both anxiety and depression, so it will be interesting to see if it gets approval for both (or neither :( (Keeping all fingers and toes crossed!)
I wonder if this drug will have a withdrawal syndrome? But I know there is no way to predict that based on the information given.
I still have some depression but not the horrible, clinical variety since having a course of rTMS. But my anxiety is crippling (rTMS doesn't help with anxiety). So, if this drug leans towards being more helpful with anxiety, that will be fine with me
I really appreciate all the information!
Posted by conundrum on April 6, 2010, at 17:33:41
In reply to Re: Technical question on new anti-depressant, posted by Katgirl on April 6, 2010, at 9:35:20
Its funny how SSRIs were created using rational drug creation methods, thinking antagonizing less receptors would be a good idea. Now it turns out many are better off when the 5 HT2A, 5HT2C, 5HT3, 5HT6, and 5HT7 receptors are blocked and only the 5HT1A and 5HT4 receptors agonised.
Posted by bleauberry on April 6, 2010, at 17:33:41
In reply to Technical question on new anti-depressant, posted by Katgirl on April 5, 2010, at 10:14:43
I don't have any thoughts on the mechanisms of the med you mentioned. A serotonin receptor blocker, nothing new. Most antipsychotics and some TCAs do what that drug does. Not as specific as that drug though.
I did want to comment that you are not alone in white knuckling it without drugs. I got a grin when I read that. Every now and then I try something, and each time I get turned away by complications I can't handle. So most of the time, I too am white knuckling it. Glad I'm not alone. You're not alone.
Posted by Katgirl on April 6, 2010, at 18:26:43
In reply to Re: Technical question on new anti-depressant » Katgirl, posted by bleauberry on April 6, 2010, at 17:33:41
Holy cow, I had no idea there was a neurotransmitter board!! Thanks for the "boot" to the right board, Dr. Bob.
Now a concern. Someone indicated that Remeron worked in a similar fashion to this drug. Remeron and I are NOT friends. Not suprising, hard to feel chummy about something that makes you feel sedated and yet angry and overstimulated at the same time! I think Remeron hit norepinephrine somehow too, though, which is probably where the problem lay for me. That was my last drug trial.
Thanks for your kind words bleauberry. I have to admit when I signed on to this site last fall, I was a bit afraid to admit I wasn't on a medication. Its not that I'm anti-med (despite what happened with the paxil), its that repeated failed drug trials and the resulting withdrawals left me worse and worse and worse. Once I regained my "footing" (poor wobbly brain! :) with rTMS I have been reluctant to upset the apple cart (geez, mixing metaphors, very bad!) by attempting anymore drugs. So, I have resolved to wait for newer drugs.
Unrealistic? Possibly. Heck, maybe even probably. I think a lot of my looking at "future" drugs may just be me trying to comfort myself. I hit a rough patch and I start searching, thinking maybe someday I will again find a medication that works for me. Until then, I continue to stay on my sleep schedule, try not to get too isolated, exercise, meditate, eat right and wait for a day when my small bubble of a world will again expand so I can do what "normal" people take for granted. Like maybe go back to school, or date or whatever it is the "normals" do. :)
OK, I got way off topic. But I am grateful to everyone on these boards. And it is good to know that I am not alone!
Posted by conundrum on April 7, 2010, at 7:50:41
In reply to Re: Technical question on new anti-depressant, posted by Katgirl on April 6, 2010, at 18:26:43
Its similar to remeron in the way a vespa is similar to a hummer. They both have wheels.
The only thing they have in common is that they block the 5 HT3 receptor, which probably won't make you feel more agressive.
I think the problem with remeron is that it is an alpha adrenergic 2 antagonist. It just cuts the negative feedback loop and just keeps increasing norepinephrine. You shouldn't experience that with this drug.
It would be interesting to see what it does though. Hope you find something that works.
Posted by Katgirl on April 7, 2010, at 10:08:24
In reply to Re: Technical question on new anti-depressant » Katgirl, posted by conundrum on April 7, 2010, at 7:50:41
Conundrum-
Your analogy (vespa vs hummer) totally cracked me up. (Even though it may have been written to highlight my lack of knowledge!!) Regardless, it made me actually laugh, which these days is a very good thing indeed. Thanks for the info!
Posted by Brainbeard on April 14, 2010, at 13:47:58
In reply to Re: Technical question on new anti-depressant, posted by Katgirl on April 7, 2010, at 10:08:24
5ht3 receptors facilitate dopamine release, so blocking them has an antidopaminergic effect. I think this has been missing from the info offered thus far. This antidopaminergic effect may have potential for alleviating OCD symptoms, as well as for countering the reward mechanism of addictions. (Ondansetron, a 5ht3-antagonist, has been investigated for both options. Ondansetron has a very short half-life, which complicates the use of the drug for such purposes. Memantine is also a 5ht3-antagonist, among other things.)
Posted by Katgirl on April 14, 2010, at 15:42:37
In reply to Re: Technical question on new anti-depressant, posted by Brainbeard on April 14, 2010, at 13:47:58
Thanks for the added information! I am tentatively hopeful about this drug. Especially that it won't induce nausea and may be good for anxiety which is what I need it for. I don't have OCD but I very much have racing thoughts, which i sometimes think are related.
This is the end of the thread.
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