Posted by King Vultan on March 28, 2004, at 10:02:02
In reply to Re: HELP..effexor/zoloft side effects ARGH!, posted by flygirl on March 27, 2004, at 13:36:02
I had also considered the possibility that he might be experiencing some symptoms of serotonin syndrome. I also agree that the potential build up of the drug to toxic levels is a concern. Depending on one's ethnicity, a certain percentage of people are what is called "poor 2D6 metabolizers," meaning that they lack sufficient levels of the CYP-450 2D6 enzyme to properly metabolize certain drugs. Almost all antidepressants, including both Zoloft and Effexor, are metabolized by this enzyme.
What happens with people who are poor 2D6 metabolizers is that when they take a drug metabolized by this enzyme, the drug can build up to dangerously high levels, as the body is not able to properly get rid of it. I note that your husband seemed to be doing better on the lower dosages and question if lowering the dosage might not be a prudent thing to try.
Of course, there is also the issue of Effexor withdrawal to throw a monkey wrench in the works, but from everything you've said, it sounds like he likely would be better off on a lower dosage of this drug. Withdrawal symptoms from lowering the dosage of Effexor are not as bad as eliminating it entirely, if my own experience is any indication.
FWIW, 3%-8.9% of caucasians are poor 2D6 metabolizers, as are 1%-4.5% of hispanics and 0%-2.4% of east Asians. The only antidepressants that are not metabolized by the 2D6 enzyme are the SSRIs Celexa and Lexapro, and the MAO inhibitors Nardil and Parnate. It is worth pointing out that Celexa and Lexapro are both metabolized by the 2C19 enzyme, another enzyme that exhibits genetic polymorphism (2.5%-6.7% of caucausians are poor metabolizers, but I'm assuming there is no relationship to being a poor 2D6 metabolizer). Nardil and Parnate are not metabolized by the CYP-450 enzyme system.
Todd
poster:King Vultan
thread:329022
URL: http://www.dr-bob.org/babble/20040325/msgs/329406.html