Background: Neuropathic pain is difficult to treat. We
identified those studies in the literature in which the
effectiveness of alpha lipoic acid as a treatment for
neuropathic pain was evaluated.
Methods: Systematic literature review. The databases
MEDLINE and EMBASE were searched using the keywords
“lipoic acid”, “thioctic acid”, “diabet*”, and the medical
subject headings (MeSH ) “thioctic acid” and “diabetes
mellitus”. Randomised placebo-controlled trials (RCTs)
and meta-analyses were selected and assessed for their
methodological quality.
Results: Five RCTs and one meta-analysis were found.
The Total Symptom Score (TSS ) was used as the primary
outcome measure. A significant improvement in the TSS
was reported in four of the RCTs. An oral or intravenous
alpha lipoic dose of at least 600 mg per day resulted in a
50% reduction in the TSS . However, compared with the
control group, the TSS reduction in most groups was less
than 30%, which is the threshold presumed to be clinically
relevant. Four RCTs were of good quality (level of evidence
1b), one RCT had methodological limitations (level 2b),
and the methodological quality of the meta-analysis was
insufficient for the purposes of this review.
Conclusion: Based on the currently available evidence,
when given intravenously at a dosage of 600 mg once daily
over a period of three weeks, alpha lipoic acid leads to a
significant and clinically relevant reduction in neuropathic
pain (grade of recommendation A). It is unclear if the
significant improvements seen after three to five weeks
of oral administration at a dosage of ≥600 mg daily are
clinically relevant.
