Posted by SLS on February 6, 2012, at 7:40:25
In reply to Re: Adding Parnate and prazosin. » SLS, posted by ed_uk2010 on February 6, 2012, at 6:31:13
> Thanks for the information Scott.
>
> >I see that Fanapt acts like prazosin at the NE alpha-1 receptor. Interesting.
>
> A large number of psych meds are alpha-1 blockers, especially TCAs and many APs (both old and new). This can cause orthostatic hypotension, dizziness and fainting/syncope. Alpha-1 antagonism isn't often thought of as a positive feature of psych meds, but I suppose it could be in some cases.I think it depends on the subtype of NE alpha-1 receptor that occurs in the brain compared to peripherally. TCA probably does not hit the right receptors in the brain.
"More recently, three subtypes of the alpha1-receptor, the alpha1A, alpha1B and alpha1D have been isolated, cloned and characterized"
http://www.mc.uky.edu/pharmacology/instruction/pha824ar/pha824ar.html
"Prazosin antagonizes phenylephrine (alpha1 agonist)-induced contractions, in vitro, and binds with high affinity to the alpha1c adrenoceptor, which is thought to be the predominant functional type in the prostate."
* Note: The NE alpha-1c receptor has been renamed to NE alpha-1d.
* Note: Prazosin is non-selective and hits all NE alpha-1 receptor subtypes, albeit with differing binding affinities.
http://www.drugbank.ca/drugs/DB00457
For a review:
http://www.nature.com/mp/journal/v8/n7/full/4001351a.html
- ScottSome see things as they are and ask why.
I dream of things that never were and ask why not.- George Bernard Shaw
poster:SLS
thread:1005781
URL: http://www.dr-bob.org/babble/20120202/msgs/1009447.html