Posted by yxibow on March 11, 2007, at 23:57:14
In reply to Re: Benzo's, posted by notfred on March 11, 2007, at 15:37:24
> > How long can Benzo's stay in your system?
>
> people are confusing 1/2 life, which does not tell you how long a drug can be tested for.
>
> Benzos are fat soluble drugs, they can be still detected at and up to a month. Flushing has limited effectiveness in fat soluble drugs, taken to Nth degree your sample will be judged invalid if it is too dilute. Other dodges with herbals
> effect pH of the sample; while this can render a test impossible it also will be detected. pH and specific gravity of the sample are measured and you can be considered having a dirty test if they are out of range.
Only some benzodiazepines are lipophilic, the lipophilic benzodiazepines have a shorter onset of action than the water soluble agents. They have a shorter CNS effect and are distributed to fat tissue. Lorazepam has a longer CNS duration of action than diazepam because diazepam is lipophilic and lorazepam is not. [Emedicine]Xanax is rather lipophilic and has a very short onset, the immediacy effect that I was mentioning before.
This isn't the complete story of benzodiazepines as they have multiple metabolites. Diazepam still has a long half life.
And then there's the general dose argument that is used which approximates nonlinear curves, so a drug is "out" of the system in 5 half lives.
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In general, high potency benzodiazepines:
Xanax, Ativan, Halcion (short half life)
Clonazepam (long half life)Low potency:
Librium, Tranxene, Valium, Dalmane (long half life)
(Am Fam Physician 2000; 61:2121-8.)
"Pharmacologic properties such as potency, half-life and lipophilicity, the duration of treatment and the rate of a dosage increase or decrease have a bearing on the occurrence of side effects. 1"
"1. Salzman C, for Task Force on Benzodiazepine Dependency, American Psychiatric Association. Benzodiazepine dependence, toxicity, and abuse: a task force report of the American Psychiatric Association. Washington, D.C.: American Psychiatric Association, 1990."
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poster:yxibow
thread:739648
URL: http://www.dr-bob.org/babble/20070308/msgs/740311.html