Type IV complex of ETC is inhibited by

Cyanide is probably the most potent inhibitor of ETC (Complex IV). It binds to Fe3+ of cytochrome oxidase blocking mitochondrial respiration leading to cell death. Cyanide poisoning causes death due to tissue asphyxia (mostly of the central nervous system) In Acute cyanide poisoning Amyl nitrite is given followed by sodium thiosulphate. This is an example of Chemical antagonism i.e. one drug binding to other making it unavailable in body.