Posted by Dave001 on August 27, 2005, at 20:13:03
I posted the following to sci.med almost verbatim, so some of it may
seem out of context.Link to citation:
<http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=abstract&list_uids=16014752>;========================================================
J Pharmacol Exp Ther. 2005 Jul 13; [Epub ahead of print]Amphetamine treatment similar to that used in the treatment of adult
ADHD damages dopaminergic nerve endings in the striatum of adult
non-human primates.Mechan-Mayne A, Yuan J, Hatzidimitriou G, Xie T, Mayne A, McCann UD,
Ricaurte GA.Johns Hopkins University.
Pharmacotherapy with amphetamine is effective in the management of
attention-deficit/ hyperactivity disorder (ADHD), now recognized in
adults, as well as in children and adolescents. Here we demonstrate that
amphetamine treatment, similar to that used clinically for adult ADHD,
damages dopaminergic nerve endings in the striatum of adult non-human
primates. Furthermore, plasma concentrations of amphetamine associated
with dopaminergic neurotoxicity in non-human primates are on the order
of those reported in young patients receiving amphetamine for the
management of ADHD. These findings may have implications for the
pathophysiology and treatment of ADHD. Further preclinical and clinical
studies are needed to evaluate the dopaminergic neurotoxic potential of
therapeutic doses of amphetamine, in children as well as adults.PMID: 16014752
===========
A cursory scan of the 43 paper says that a reduction
of some 30-50% of dopamine neuronal markers were observed after four
weeks. The subjects received oral preparations (self-administered) of
a 3:1 ratio of the d- and l- amphetamine isomers (sounds familiar). The
doses were similar to the upper end of the range used in medicine, as
were plasma drug concentrations. Because "amphetamine" is sometimes
misappropriated to derivatives and structurally similar chemicals, I
should point out that the study did in fact involve amphetamine.Have any of you seen a decent article (preferably peer-reviewed) that
gives an estimation of a human NOAEL of amphetamine (d- or racemic), in
addition to, of course, its basis? None of the animal studies that I've
read thus far provide justification for the current prescribing
guidelines or the FDA's MRTD (whether such evidence should be necessary
to justify its medical use is another subject entirely). Postmortem
histopathological observations of former methamphetamine addicts are
wholly unimpressive.Methylphenidate doesn't appear nearly as neurotoxic as amphetamine in
animal studies (indeed, it has even prevented amphetamine-induced
neurotoxicity in some studies), so I'm interested to know why the latter
is often used in place of the former, when the difference is usually
only marginal.BTW, is Johns Hopkins known for a tendency toward bias concerning the
controversial use of these medicines?
poster:Dave001
thread:547372
URL: http://www.dr-bob.org/babble/20050827/msgs/547372.html