POR and Hypoglycemia: Despite these findings, limited data from small‐sized studies have not provided convincing evidence of the association between CYP2C9 poor‐metabolizer genotypes and the risk of SU‐induced hypoglycaemia.10 A small study recently showed that a common polymorphism in the gene encoding a CYP450 redox partner, enzyme P450 oxidoreductase (POR), POR*28 (A503V, rs1057868), could mask the effect of CYP2C9 variants on the risk of hypoglycaemia associated with SU treatment.11 POR transfers electrons from NADPH to the CYP450 enzymes and is essential for their activity.