Posted by Larry Hoover on August 30, 2008, at 15:14:16
In reply to Re: How long does Alprazolam (Xanax) stay detectable.., posted by robbieboy74 on August 30, 2008, at 13:29:23
> So I do need to know the number of hours approx. The max and min and mean or mode or quantiles would be nice. but i bet only the first two are available.
>
> Thanks so much!
>
> Sincerely,
> Rob!It's pretty hard to say with any certainty at all. Lots of variables.....individual dose, chronicity of dose, metabolic rate, detection method....
The metabolic rate issue gives a factor of four range, all by itself. "Using a specific assay methodology, the mean plasma elimination half-life of alprazolam has been found to be about 11.2 hours (range: 6.3-26.9 hours) in healthy adults." Note, that's healthy adults. Older people, drinkers, hepatitis increase the half-life.
The usual rule for plasma clearance is five half-lives (1/16 of peak dose remaining), giving a range of 32 to 135 hours for healthy people.
Looking at lab websites, I found one that said: "The half-lives of benzodiazepines range from 2 to 40 hours, depending on the duration of use. Benzodiazepines may be detected in the urine up to 10 days after use." Applying an adjustment for the upper range for alprazolam half-life might give you detection for as long as a week.
However, a different lab website, with the same limit of detection (200 ng/mL), says "up to 72 hours." http://www.ncsconline.org/wc/publications/res_judedu_substanceabusematerial19pub.pdf
The primary enzyme pathway is 3A4, which is an inducible enzyme, i.e. the rate can be increased by other substances. That would be to your benefit, but be aware, there are far more rate inhibitors than there are inducers. Sample list here: http://smbrower.com/mediawiki/index.php/CYP_3A4_Inducers
Good luck.
Lar
poster:Larry Hoover
thread:849204
URL: http://www.dr-bob.org/babble/20080822/msgs/849273.html