Plasma concentration of free carnitine is in dynamic balance with acylcarnitines with the acyl to free carnitine ratio of ≤ 0.4 being considered normal [65], however, in uremic patients, this balance is disrupted, and this ratio is altered because of a larger amount of free carnitine is esterified to acyl-carnitine to "buffer" the excess of acyl groups, modulating the bound CoA to free CoA [68]. This may cause several metabolic disturbances at the cellular level, including impaired mitochondrial fatty acid oxidation and energy production, accumulation of toxic acyl moieties, and inhibition of key enzymes of metabolic pathway [69]. These metabolic abnormalities may lead to the several clinical alterations often observed in these patients, such as muscle weakness and myopathy, loss of body protein and cachexia, insulin resistance and glucose intolerance, plasma lipid abnormalities, anemia refractory to erythropoietin (EPO) treatment, cardiomyopathy, and intradialytic symptoms [70,71,72]. Thus, the imbalanced in acyl/free carnitine ratio may explain the higher risk of patients with chronic renal failure to CIAKI. However, Carnitine supplementation may contribute to the regeneration of sequestrated free CoA and to maintain normal metabolic processes [66,67].