Local anesthetics (benzocaine and lidocaine) and EMLA cream cause methemoglobinemia.[48,49] As methylene blue is converted to leukomethylene blue by nicotinamide adenine dinucleotide phosphate, and leukomethylene blue converts methemoglobin to hemoglobin, methylene blue is used to treat methemoglobinemia.[48] Methemoglobinemia induced by EMLA cream was treated with methylene blue (Case No. 8). This evidence concerns the gene HBG2 and methemoglobinemia.