Methylthioninium chloride, commonly called<unk> , is a salt used as a dye and as a medication.<unk>  is a thiazine dye. It works by converting the ferric iron in hemoglobin to ferrous iron. As a medication, it is mainly used to treat methemoglobinemia. Specifically, it is used to treat methemoglobin levels that are greater than 30% or in which there are symptoms despite oxygen therapy. It has previously been used for cyanide poisoning and urinary tract infections, but this use is no longer recommended.<unk>  is typically given by injection into a vein. Common side effects include headache, vomiting, confusion, shortness of breath, and high blood pressure. Other side effects include serotonin syndrome, red blood cell breakdown, and allergic reactions. Use often turns the urine, sweat, and stool<unk>  to green in color. While use during pregnancy may harm the baby, not using it in methemoglobinemia is likely more dangerous.<unk>  was first prepared in 1876, by Heinrich Caro. It is on the World Health Organization's List of Essential Medicines.
Methylene blue
Fomepizole
Sodium thiosulfate 
Dimercaprol
Disufenton sodium
Amylmetacresol
Fenpentadiol
Glutaraldehyde