Notes: N-Methyl-4-pyridone-5-carboxamide is a metabolite of nicotinic acid and a uremic toxin.{66100,66101} Plasma levels of N-methyl-4-pyridone-5-carboxamide are increased and positively correlated with serum levels of malondialdehyde (MDA) in patients with chronic kidney disease (CKD).{66101}