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Dr. Bob is Robert Hsiung, MD,
bob@dr-bob.orgShown: posts 1 to 11 of 11. This is the beginning of the thread.
Posted by linkadge on December 12, 2007, at 14:03:26
According to medscape, venlafaxine is structurally similar to phenylcyclidine.
"Venlafaxine is structurally similar to phencyclidine and thus should not be discontinued abruptly".
Does this have any bearing on its mechanism of action?
Crazy.
Linkadge
Posted by Phillipa on December 12, 2007, at 14:27:25
In reply to venlafaxine structurally similar to PCP, posted by linkadge on December 12, 2007, at 14:03:26
So does that mean that for some it work like PCP? Or is the chemical structure just similar and what does that really mean about effexor? Phillipa
Posted by torachan on December 12, 2007, at 17:40:51
In reply to venlafaxine structurally similar to PCP, posted by linkadge on December 12, 2007, at 14:03:26
If you're a chemically knowledgeable, could you please confirm if these reports of Effexor being chemically similar to PCP are correct. If it's true, it will greatly impact on my decision to continue using Effexor. I will NOT use a drug related to PCP to treat my primarily anxious related symptoms. I did enough recreational drug use in my teens; I don't need any more of its damaging effects.
Posted by linkadge on December 12, 2007, at 17:48:55
In reply to Re: venlafaxine structurally similar to PCP)Link, posted by torachan on December 12, 2007, at 17:40:51
I am mainly wondering if there is any similarity in psychological actions. I read in other places, that venlafaxine can produce a false positive for PCP.
I don't know if I'd conclude that one will be as psychologically damaging as the other.
I do know that venlafaxine makes me slightly paranoid. It feels a bit more psychoactive than SSRI's, but thats just my experiences.
Linkadge
Posted by torachan on December 12, 2007, at 18:45:54
In reply to Re: venlafaxine structurally similar to PCP)Link, posted by linkadge on December 12, 2007, at 17:48:55
Yeah, I read the same thing, that venlafaxine has produced false positives for PCP in random drug tests used by law enforcement or employers. And if it's chemically similar, as your research on medscape suggests, how could it now have the same psychological effects.
I have some experience with recreational drug use--not sure if I ever tried PCP--and Effexor, but I'm guessing the recreational drug form of PCP is either more pure or is ingested at higher levels than what Effexor is used at in therapeutic levels. Actually, I read the blood concentration level is about three of four fold less than a common dose of PCP. Regardless, I'm still reluctant to use such a drug for my primarily anxiety related symptoms.
I'm just puzzled as to why I couldn't tolerate the start-up anxiety of the SSRI's--I've tried LEX/Celexa and Paxil recently--when people have claimed them to be less stimulating. They actually DID make me feel like I was taking speed ie;PCP.
Posted by torachan on December 12, 2007, at 18:50:13
In reply to Re: venlafaxine structurally similar to PCP)Link, posted by torachan on December 12, 2007, at 18:45:54
Meant to say, "how could it not have the same psychological effects?"
Posted by linkadge on December 12, 2007, at 19:14:39
In reply to Re: venlafaxine structurally similar to PCP)edit^, posted by torachan on December 12, 2007, at 18:50:13
Well I do know that venlafaxine rarely produces euphoria. (Well it does in some, but probably a lot less often than with PCP). I don't think there is a big street market for venlafaxine.
It is possible that euphoria could only be achieved at doses that would cause uncomfortable cardiovascular reactions (as effexor can raise heartrate).
I don't believe that venlafaxine is abused in the same way that PCP is.
There could be subtle similarities thought. I have noticed that effexor gives me some mild paranoid like reactions, like people are reading my mind. I also get some dark feelings on it too, like I feel ...evil somtimes. I also get some mild visual distortions stuff looking surreal, or otherworldly.
It could be other stuff, as I do have problems, but I thought it felt it was was working on another axis as other AD's.
Linkadge
Posted by cumulative on December 12, 2007, at 21:13:31
In reply to venlafaxine structurally similar to PCP, posted by linkadge on December 12, 2007, at 14:03:26
Chemicals that vary only slightly in structure can have pretty radically different effects. For instance: ethanol and methanol.
Posted by djmmm on December 13, 2007, at 20:08:50
In reply to venlafaxine structurally similar to PCP, posted by linkadge on December 12, 2007, at 14:03:26
> According to medscape, venlafaxine is structurally similar to phenylcyclidine.
>
> "Venlafaxine is structurally similar to phencyclidine and thus should not be discontinued abruptly".
>
> Does this have any bearing on its mechanism of action?
>
> Crazy.
>
> Linkadge
>
>
>
I have to say, looking at both chemical structures, PCP and effexor are chemically dissimilar. PCP is tricyclic. Effexor is a phenylthylamine (closer to amphetamine)http://www.clinchem.org/content/vol48/issue4/images/medium/cy0423690001.gif
Posted by linkadge on December 13, 2007, at 22:27:53
In reply to Re: venlafaxine structurally similar to PCP, posted by djmmm on December 13, 2007, at 20:08:50
Interesting. I have always wondered if its relation to amphetamine has anything to do with its effect on blood pressure.
For instance, Paroxetine on paper has a higher binding ratio of noradrenaline reuptake inhibition to serotonin reuptake inhibition, yet you don't get the same blood pressure warnings with paxil.
Linkadge
Posted by rgb on December 15, 2007, at 17:20:20
In reply to Re: venlafaxine structurally similar to PCP, posted by linkadge on December 13, 2007, at 22:27:53
I wouldn't worry, torachan - PCP is mainly an NMDA antagonist, causing dissociation. It's also quite dopaminergic IIRC... Venlafaxine is a serotonin and, to a lesser degree, noradrenaline reuptake inhibitor.
This is the end of the thread.
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