Here is the result of small clinical trials in humans in Germany as of
1999. There may be more positive evidence since then. High pyridoxine
supplementation usually in excess of 600 mg./day has resulted in
neuropathy in a small number of people. They were taking it for carpal
tunnel syndrome. They were also taking it w/o other B vitamins and the
condition was reversible. Personally I have taken 1000 mg/d for
extended periods w/o side effects. It's probably best to steer clear
of supplementation IMHO.
Exp Clin Endocrinol Diabetes. 1999;107(7):421-30.Links
Alpha-lipoic acid in the treatment of diabetic polyneuropathy in
Germany: current evidence from clinical trials.Ziegler D, Reljanovic
M, Mehnert H, Gries FA.
Diabetes-Forschungsinstitut an der Heinrich-Heine-Universit=E4t,
D=FCsseldorf, Germany. dan.ziegler@[EMAIL PROTECTED]
neuropathy represents a major health problem, as it is
responsible for substantial morbidity, increased mortality, and
impaired quality of life. Near-normoglycaemia is now generally
accepted as the primary approach to prevention of diabetic neuropathy,
but is not achievable in a considerable number of patients. In the
past two decades several medical treatments that exert their effects
despite hyperglycaemia have been derived from the experimental
pathogenetic concepts of diabetic neuropathy. Such compounds have been
designed to improve or slow the progression of the neuropathic process
and are being evaluated in clinical trials, but with the exception of
alpha-lipoic acid (thioctic acid) which is available in Germany, none
of these drugs is currently available in clinical practice. Here we
review the current evidence from the clinical trials that assessed the
therapeutic efficacy and safety of thioctic acid in diabetic
polyneuropathy. Thus far, 15 clinical trials have been completed using
different study designs, durations of treatment, doses, sample sizes,
and patient populations. Within this variety of clinical trials, those
with beneficial effects of thioctic acid on either neuropathic
symptoms and deficits due to polyneuropathy or reduced heart rate
variability resulting from cardiac autonomic neuropathy used doses of
at least 600 mg per day. The following conclusions can be drawn from
the recent controlled clinical trials. 1.) Short-term treatment for 3
weeks using 600 mg of thioctic acid i.v. per day appears to reduce the
chief symptoms of diabetic polyneuropathy. A 3-week pilot study of
1800 mg per day given orally indicates that the therapeutic effect may
be independent of the route of administration, but this needs to be
confirmed in a larger sample size. 2.) The effect on symptoms is
accompanied by an improvement of neuropathic deficits. 3.) Oral
treatment for 4-7 months tends to reduce neuropathic deficits and
improves cardiac autonomic neuropathy. 4.) Preliminary data over 2
years indicate possible long-term improvement in motor and sensory
nerve conduction in the lower limbs. 5.) Clinical and postmarketing
surveillance studies have revealed a highly favourable safety profile
of the drug. Based on these findings, a pivotal long-term multicenter
trial of oral treatment with thioctic acid (NATHAN I Study) is being
conducted in North America and Europe aimed at slowing the progression
of diabetic polyneuropathy using a clinically meaningful and reliable
primary outcome measure that combines clinical and neurophysiological
assessment.
PMID: 10595592 [PubMed - indexed for MEDLINE]
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