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Dr. Bob is Robert Hsiung, MD,
bob@dr-bob.orgShown: posts 1 to 12 of 12. This is the beginning of the thread.
Posted by linkadge on January 19, 2007, at 15:31:07
http://jpet.aspetjournals.org/cgi/content/full/283/3/1305
"Of particular interest were the findings that paroxetine, generally thought of as a selective SERT antagonist, possesses moderately high affinity for the NET and that venlafaxine, which has been described as a "dual uptake inhibitor", possesses weak affinity for the NET"
Linkadge
Posted by med_empowered on January 19, 2007, at 17:46:03
In reply to Is paroxetine more dual action than venlafaxine ?, posted by linkadge on January 19, 2007, at 15:31:07
maybe this explains the hellish withdrawals from paxil? I mean, along with the short half-life.
Posted by linkadge on January 19, 2007, at 17:58:27
In reply to Re: Is paroxetine more dual action than venlafaxin, posted by med_empowered on January 19, 2007, at 17:46:03
Paxil felt different from other SSRI's.
Linkadge
Posted by Phillipa on January 19, 2007, at 22:30:53
In reply to Re: Is paroxetine more dual action than venlafaxin, posted by linkadge on January 19, 2007, at 17:58:27
Paxil at l0mg with xanax was the only and first ad I was on that worked for two years til I went off it. I didnt have withdrawals just bit a tinier piece off each day. Love Phillipa
Posted by blueberry1 on January 20, 2007, at 8:43:05
In reply to Is paroxetine more dual action than venlafaxine ?, posted by linkadge on January 19, 2007, at 15:31:07
Somewhere at pubmed, don't remember exactly where, there was an abstract reporting on a survey of hundreds of physicians for their opinions on antidepressants. Paxil was the number one antidepressant for efficacy. Zoloft and effexor were right behind it. Other meds got higher scores in terms of easier side effects but less efficacy.
It seems like any drug that has norepinephrine reuptake is harder to withdraw from. Effexor and paxil, and now duloxetine, and of course tramadol, seem to be the ones with the most complaints of difficult flu-like withdrawals. Since paxil is one of them, maybe it does have some norepinephrine reuptake just based on that. Don't know.
Posted by linkadge on January 20, 2007, at 10:02:24
In reply to Re: Is paroxetine more dual action than venlafaxine ?, posted by blueberry1 on January 20, 2007, at 8:43:05
Paxil and venlafaxine supposedly also have the greates suicide risk attributions (?)
Linkadge
Posted by Klavot on January 20, 2007, at 10:57:55
In reply to Re: Is paroxetine more dual action than venlafaxine ?, posted by blueberry1 on January 20, 2007, at 8:43:05
To my knowledge, Wellbutrin has no withdrawal issues yet it involves norepinephrine reuptake inhibition. Perhaps the problematic combination for withdrawal is serotonin + norepinephrine reuptake inhibition?
Klavot
> It seems like any drug that has norepinephrine reuptake is harder to withdraw from. Effexor and paxil, and now duloxetine, and of course tramadol, seem to be the ones with the most complaints of difficult flu-like withdrawals. Since paxil is one of them, maybe it does have some norepinephrine reuptake just based on that. Don't know.
Posted by Quintal on January 20, 2007, at 13:18:10
In reply to Re: Is paroxetine more dual action than venlafaxine ?, posted by Klavot on January 20, 2007, at 10:57:55
I think Paxil is usually listed as being one of the most potent ihhibitors of serotonin reuptake among the SSRIs. Not sure about Zoloft but maybe that is another reason why Paxil withdrawals are so bad?
Q
Posted by Larry Hoover on January 20, 2007, at 13:24:53
In reply to Is paroxetine more dual action than venlafaxine ?, posted by linkadge on January 19, 2007, at 15:31:07
> http://jpet.aspetjournals.org/cgi/content/full/283/3/1305
>
> "Of particular interest were the findings that paroxetine, generally thought of as a selective SERT antagonist, possesses moderately high affinity for the NET and that venlafaxine, which has been described as a "dual uptake inhibitor", possesses weak affinity for the NET"
>
>
> LinkadgeThe Ki (concentration units) of paroxetine binding affinity to the norepinephrine transporter is about one-tenth that of venlafaxine, i.e. equal inhibition of the transporter at one-tenth the concentration. Yes, the paper you cite is correct.
Lar
Posted by theo on January 20, 2007, at 13:38:08
In reply to Is paroxetine more dual action than venlafaxine ?, posted by linkadge on January 19, 2007, at 15:31:07
Paxil does definitly effect both better than other SSRI's in speaking with 3 different doctors. Paxil worked miracles for me even after stopping and restarting, BUT I not only had delayed ejaculation but couldn't get an erection. It really sucks when you find the best medicine that works but it makes me 100% sexually dysfunctional.
Posted by linkadge on January 20, 2007, at 19:00:29
In reply to Re: Is paroxetine more dual action than venlafaxine ?, posted by theo on January 20, 2007, at 13:38:08
Paroxetine is one of the most potent SSRI's too, so I don't know how the ratio of ser/nor compares with that of effexor, or cymbalta for that matter.
Paxil kindof felt like a TCA. It also made me feel a little bit psychotic which none of the other SSRI's did.
Linkadge
Posted by psychobot5000 on January 21, 2007, at 20:30:10
In reply to Re: Is paroxetine more dual action than venlafaxine ?, posted by linkadge on January 20, 2007, at 19:00:29
>
> Paxil kindof felt like a TCA. It also made me feel a little bit psychotic which none of the other SSRI's did.
>
> LinkadgeAccording to various things I've read, Paxil is (according to metaanalyses) very slightly more effective than other SSRIs (at least before Celexa). It also has higher anticholinergic effects, and maybe H1 blocking too, which are believed to account for some of its sedation.
I saw one chart about a year ago, with various binding affinities of tricyclics and SSRIs and what-nots, and had to keep checking back and forth in confusion, because Paroxetine was clearly listed there with a modestly -higher- noradrenaline reuptake inhibition than Effexor. I had always been told effexor was fairly weak on NA, but really! Weaker than a conventional SSRI? How do they get off calling it an SNRI then?
In any case, the picture I get from Paxil is: 5-ht reuptake inbition, modest NA reuptake inhibition, and receptor effects on ACH and possibly H1. Sounds a hell of a lot like a tricyclic to me!
But I can't help but think we're missing something, if Effexor/Venlafaxine has gotten away with claiming to be an SNRI for all this time...
This is the end of the thread.
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