As many as 50% of people with diabetes develop peripheral neuropathy over a 25-year period due to nerve damage. Those who develop painful diabetic neuropathy (PDN) suffer symptoms that include tingling and numbness that may be accompanied by excruciating, stabbing, or burning pain mainly in the legs and feet. Currently, there are no drugs that can slow or reverse the progression of PDN. Management of PDN is symptomatic and through glycemic control. Although the underlying cause of PDN is unclear, mitochondrial dysfunction leading to oxidation and inflammation has been suspected to play a role. Coenzyme Q10 is an important component of energy production via the electron transport chain of the mitochondria and has been shown to have antioxidant and anti-inflammatory properties. Though coenzyme Q10 has shown promise in neuropathic pain management, improving pain associated with fibromyalgia, there are mixed results when coenzyme Q10 was used as a monotherapy for PDN. In their most recent paper published in 2022 in European Journal of Clinical Pharmacology, Amini et al investigated if adding coenzyme Q10 may improve the symptoms of patients with PDN prescribed pregabalin treatment.
The study was an eight-week parallel, randomized double-blind placebo-controlled trial. One hundred twelve patients with PDN received pregabalin (150 mg/d) with either: 1) 100 mg/8h Q10 or 2) placebo for eight weeks. Pain relief was measured by changes in ratings for pain intensity, pain-associated sleep interference scores, and patient and physician global impression of change. Interestingly, the results support the use of Q10 in conjunction with PDN treatment to reduce pain. Greater improvements in pain indices occurred after a minimum of four weeks of Q10 supplementation. By week 8, patients receiving Q10 reported significantly greater decreases in pain scores, pain-associated sleep interference, and patient and physician global impressions of change.
Overall, the study was well designed and conducted. There was a sufficient number of patients included. Inclusion and exclusion criteria of the patients was reasonable, and the randomized, placebo-controlled study designed minimized bias in the outcomes. The groups were well matched for baseline characteristics. The rationale for the dosing was also well explained as the dose was based on the dose given in previous studies that showed improvements in pain outcomes in fibromyalgia treated with pregabalin. It would have been important to disclose what the placebo was to ensure there was no effect of the placebo on the measured outcomes, which the authors did not do. It would have also been interesting if the authors would have examined whether there was a sex-based response to supplementation. Despite these concerns, the study provides good evidence that adjuvant supplementation with coenzyme Q10 at a dose of 100 mg/8 h may enhance pain reduction in those prescribed pregabalin. Future studies should determine whether the observed improvements in pain are sustained over longer periods of supplementation.
Amini P, Sajedi F, Mirjalili M, Mohammadi Y, Mehrpooya M. Coenzyme Q10 as a potential add-on treatment for patients suffering from painful diabetic neuropathy: results of a placebo-controlled randomized trial. Eur J Clin Pharmacol. 2022 Dec;78(12):1899-1910. doi: 10.1007/s00228-022-03407-x. Epub 2022 Oct 22. PMID: 36273066.