Posted by fachad on April 5, 2002, at 11:51:28
In reply to FACHAD: 2 questions 4 U (1/2 lives revisited!), posted by Janelle on April 4, 2002, at 23:50:20
I think your question turns on exactly what you mean by the word "gone".
5 half-lives was what one pdoc told me was “gone enough” to be considered adequate for wash out to start another drug.
Elizabeth's 7 half lives uses a definition of "gone" as less than 1% of the original concentration remaining.
So it depends on what you mean by gone. If you mean totally absent from the body, even that is going to depend on how sensitive the equipment is that is used to analyze your blood.
If you had an analytical GC/MS set up that could detect concentrations down to ppt (parts per trillion) you might find a molecule or two of the drug floating around years after you stopped taking the drug.
But in science and medicine words like "gone" have *practical*, not *absolute* definitions. So if there is so little of the drug that it does not exert any clinical effects, or so little that it does not react with another drug, it is said to be gone, even if there's some really there.
poster:fachad
thread:101843
URL: http://www.dr-bob.org/babble/20020402/msgs/101982.html