Lack of a Clinically Significant Pharmacokinetic Interaction Between Pregabalin and Thioctic Acid in Healthy Volunteers

Scientific opinion on the relationship between intake of alpha-lipoic acid (thioctic acid) and the risk of insulin autoimmune syndrome

Following a request from the European Commission, the EFSA Panel on Nutrition, Novel Foods and Food Allergens (NDA) was asked to deliver an opinion on the relationship between alpha-lipoic acid (ALA) and the risk of insulin autoimmune syndrome (IAS). The Panel was also asked to advise on the dose below which ALA added to foods is not expected to cause IAS. A review of all possible adverse effects associated with consumption of ALA was not requested. This mandate refers to the procedure under Article 8(2) of Regulation (EC) No 1925/2006 on addition of vitamins, minerals and certain other substances to foods. No pre-established rule exists for the evaluation of the safety of foods when classical toxicity tests cannot be used, e.g. for autoimmune diseases. Published scientific evidence was retrieved through comprehensive literature searches, particularly 49 case reports in which IAS developed following ALA consumption. In all cases, IAS resolved after a few weeks to months when ALA was discontinued. No publication linking the intake of ALA naturally occurring in foods to IAS was identified. The Panel concludes that the consumption of ALA added to foods, including food supplements, is likely to increase the risk of developing IAS in individuals with certain genetic polymorphisms, who cannot be readily identified without genetic testing. The plausible mechanism of such an effect has not yet been fully elucidated. The incidence of IAS in Europe is low and likely lower than in Japan where it has been estimated to be 0.017 per 100,000 inhabitants in 2017-2018. Considering the limited data available, the risk associated with the development of IAS following ALA consumption cannot be quantified precisely. An ALA dose below which IAS is not expected to occur is likely to vary between individuals and cannot be determined from the available data.

Current concepts in the management of diabetic polyneuropathy

Diabetic sensorimotor polyneuropathy (DSPN) is encountered in approximately one-third of people with diabetes. This, in turn, might markedly impoverish their quality of life, mainly owing to neuropathic pain and foot ulcerations. Painful DSPN might be as frequent as 25% in diabetes patients. Symptoms as a result of DSPN typically comprise pain, paresthesia and numbness in the distal lower limbs. Asymptomatic DSPN might reach 50% among patients with this condition. Unfortunately, DSPN is still not adequately diagnosed and treated. Its management has three priorities: (i) lifestyle improvement, near-normoglycemia and multifactorial cardiovascular risk intervention; (ii) pathogenesis-oriented pharmacotherapy; and (iii) symptomatic alleviation of pain. Intensive diabetes therapy showed evidence for favorable effects on the incidence and deterioration of DSPN in type 1 diabetes, but not type 2 diabetes. Among pathogenesis-oriented treatments, α-lipoic acid, actovegin, benfotiamine and epalrestat are currently authorized to treat DSPN in several countries. Symptomatic therapy uses analgesics, notably antidepressants, opioids and anticonvulsants, reducing pain by ≥50% in approximately 50% of individuals, but might be limited, particularly by central nervous system-related adverse events. Local treatment with the capsaicin 8% patch might offer an alternative. In addition to pain relief, therapy should improve sleep, mobility and quality of life. In conclusion, multimodal treatment of DSPN should consider the individual risk profile, pathogenetic treatment and pain management using pharmacotherapy (combinations, if required), as well as non-pharmacological options.

Mitochondrial Dysfunction and Alpha-Lipoic Acid: Beneficial or Harmful in Alzheimer's Disease?

Alzheimer's disease (AD) is a neurodegenerative disorder characterised by impairments in the cognitive domains associated with orientation, recording, and memory. This pathology results from an abnormal deposition of the β-amyloid (Aβ) peptide and the intracellular accumulation of neurofibrillary tangles. Mitochondrial dysfunctions play an important role in the pathogenesis of AD, due to disturbances in the bioenergetic properties of cells. To date, the usual therapeutic drugs are limited because of the diversity of cellular routes in AD and the toxic potential of these agents. In this context, alpha-lipoic acid (α-LA) is a well-known fatty acid used as a supplement in several health conditions and diseases, such as periphery neuropathies and neurodegenerative disorders. It is produced in several cell types, eukaryotes, and prokaryotes, showing antioxidant and anti-inflammatory properties. α-LA acts as an enzymatic cofactor able to regulate metabolism, energy production, and mitochondrial biogenesis. In addition, the antioxidant capacity of α-LA is associated with two thiol groups that can be oxidised or reduced, prevent excess free radical formation, and act on improvement of mitochondrial performance. Moreover, α-LA has mechanisms of epigenetic regulation in genes related to the expression of various inflammatory mediators, such PGE2, COX-2, iNOS, TNF-α, IL-1β, and IL-6. Regarding the pharmacokinetic profile, α-LA has rapid uptake and low bioavailability and the metabolism is primarily hepatic. However, α-LA has low risk in prolonged use, although its therapeutic potential, interactions with other substances, and adverse reactions have not been well established in clinical trials with populations at higher risk for diseases of aging. Thus, this review aimed to describe the pharmacokinetic profile, bioavailability, therapeutic efficacy, safety, and effects of combined use with centrally acting drugs, as well as report in vitro and in vivo studies that demonstrate the mitochondrial mechanisms of α-LA involved in AD protection.