Posted by linkadge on January 4, 2008, at 13:47:59
In reply to Pharmacogenetic and Receptor Question, posted by garyengelm on January 3, 2008, at 21:23:48
>Serzone blocks 5HT2a receptors and Noradrenaline >reuptake. I've read that it has no affinity for >Serotonin receptors and other sites say it has a >small affinity of blocking the reuptake of >Serotonin. I thought it just turned off the >autoreceptor.
From what I understand from doing a search on http://pdsp.med.unc.edu/pdsp.php
Serzone is a moderate serotonin uptake inhibitor, weaker than most SSRI's, but still this is present. It acts as an agonist at 5-ht1a, an antagonist at 5-ht2a/c. It is a little weaker a norepinephrine reuptake inhibitor than a serotonin uptake inhibitor. It also posesses antihistamine effects.
>Lexapro of course blocks the reuptake of >Serotonin at 5HT1a receptors, and is metabolized >by 2D6 and 2C19.Lexapro has no particular affinity for 5-ht1a that I know of, it is a releativly selctive serotonin uptake inhibitor with little affinity for other neurotransmitter sites.
>So here is my question: ????????????>Why do I get so sick that I have to stop the >Lexapro on day 4,5,6 or 7 ?
Probably because GI disturbance and nausia are well documented side effects. These side effects tend to decrease over time, but sometimes require discontinuation. SSRI's can activate 5-ht3 receptors in the stomach and cause nasty nausia for some people.
>Is the fact that 2D6 >enzyme is being used for >all three of my meds and the plasma >concentration of the Lexapro getting higher? or >is it possible that the Serzone plasma >concentrations are getting to high ? I found an >article that stated that metoprolol plasma >concentrations double when taking lexapro due to >the 2D6 enzyme.Possibly, I'm not too up on interactions of metabolism. Lexapro has a slight inhibitory effect on the 2d6 enzyme which might increase the levels of one of the metabolites of serzone, or metoprolol, but I can't see that causing nausia. I can't find that lexapro is itself metabolized by cyp-2d6.
Linkadge
poster:linkadge
thread:804095
URL: http://www.dr-bob.org/babble/20071225/msgs/804213.html