Posted by Crotale on June 19, 2008, at 22:24:40
In reply to Re: Trazadone is perfectly safe with Emsam!!, posted by dcruik518 on June 18, 2008, at 18:19:26
> I don't understand this very well, but my doctor mentioned and recently read something interesting about why certain people may be more susceptible to serotonin syndrome. There is a genetic liver abnormality in about 7% of caucasians, an inability to properly metabolize drugs of the cyp450 class, I believe, and this leads sometimes to blood levels of up to 30 times what one would normally expect.
Cytochrome P450 is a class of liver enzymes which catalyze the metabolism of certain drugs. A small percentage of mainly Caucasians have a deficiency in a particular cytochrome p450 enzyme, specifically cytochrome p4502d6. Therefore these individuals don't metabolize certain drugs normally, namely those whose metabolism is catalyzed by this enzyme. (Different cytochrome enzymes are involved in the metabolism of different types of drugs.) I gather that this enzyme deficiency is quite rare.
Drugs can also competitively inhibit one or more cytochrome p450 enzymes. This is how drug interactions occur in which one drug causes the serum level of another one to rise. Prozac and Paxil are especially notorious for causing such interactions.
When I took desipramine, I had a seizure. The hospital measured my serum desipramine level and found that it was several times what it was supposed to be. The reason was a mystery, as none of the other drugs I was taking were known to have a pharmacokinetic interaction with TCAs. They thought I might have this enzyme deficiency, and I had to go off the desipramine as a result. It was a bummer, since it was working for me pretty well.
Crotale
poster:Crotale
thread:826808
URL: http://www.dr-bob.org/babble/20080617/msgs/835573.html