Posted by Larry Hoover on August 14, 2008, at 18:08:40
In reply to PRISTIQ and Metabolite/properties, posted by B2chica on August 14, 2008, at 13:32:26
> i know i'm not getting responses from questions of pristiq cuz no ones probably on it but i have one more question.
>
> if pristiq is a metabolite of Effexor(ER?)
> and the properites of Effexor are:
> 5-HT reuptake inhibition +++
> NE reuptake inhibition ++
> DA reuptake inhibition +
>
> would pristiq's properites be the same?Pristiq is O-desmethylvenlafaxine, the product of the P450 enzyme 2D6 acting on venlafaxine (Effexor). The activity of the 2D6 enzyme is highly variable, so Pristiq bypasses this concern altogether. People who can't effectively metabolize Effexor at 2D6 are much more likely to have intolerable GI side-effects, and others.
As for binding affinities, Pristiq is similar at the 5-HT transporter, slightly stronger at the NE transporter, and has almost no effect at the dopamine transporter.
One significant difference in the two drugs is half-life. Effexor is listed at ~5 hours, whereas Pristiq is ~11. Pristiq is also relatively slowly absorbed, hitting Tmax (highest blood concentration) 7.5 hours after ingestion. So, you're much less likely to suffer from peak/trough concentration fluctuations.
Best,
Lar
poster:Larry Hoover
thread:846195
URL: http://www.dr-bob.org/babble/20080814/msgs/846248.html