Posted by Larry Hoover on August 31, 2004, at 9:19:46
In reply to Re: Ecstasy safely converted and prescribed? » Larry Hoover, posted by Dave001 on August 31, 2004, at 8:56:43
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> > The first abstract below demonstrates this relationship nicely. Note that the threshold for brain damage, or even abnormal brain chemistry post-use, is greater than 4 mg/kg (by interperitoneal injection, not oral), a dose three times the typical human dose, employing a route of intake not normally employed by humans. Only
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> The study you're quoting involves rats. You can't directly compare animal doses to human doses without first calculating the human equivalent dose (HED) which takes into account such things as body surface area. To get the HED for rats you should multiply the dose above by 0.16. So 4 mg/kg * 0.16 = 0.64 mg/kg. That's a total dose of only 38.4 mg in your 60 kg human. Repeated dosing of MDMA and amphetamines gets even more complicated because rats metabolize the drug so much faster than humans.
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> Dave
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> <snip>I appreciate the digression into uncertainties of estimate. There are always assumptions made in cross-species comparisons, of course. There are also different ways to estimate HED (I assume yours is BW to the 2/3 power, rather than the metabolic parameter BW to the 3/4). Primate studies are probably more applicable, and the same pattern is found as in the rats. I.e. only extremely high doses, or recurrent use without sufficient recovery time, lead to measurable neuronal damage or changes in neurotransmitter concentrations. Another variable to consider is antioxidant status, and I wonder if e.g. ravers aren't a little more likely to eat poorly?
By no means was I suggesting the referenced article was conclusive, but merely suggestive. There is a toxic threshold, and the issue of exceeding that threshold is not clearly defined in humans.
Lar
poster:Larry Hoover
thread:383476
URL: http://www.dr-bob.org/babble/20040830/msgs/384643.html