In case of cyanide poisoning, antidote of amyl nitrite is given. This is an example of:

Cyanide inhibits ETC complex 4 and hence a powerful toxin. 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. Mechanism of action of amyl nitrite: Amyl nitrite conves Hb - Met Hb - sequester CN by making complex - complex can be thrown out of body. Hence, Amyl nitrite makes CN unavailable in the body. Other Options:- Receptor antagonism:- In this, a type of receptor ligand/drug = blocks a biological response by binding to and blocking a receptor. Physical antagonist:-It is a type of antagonist that is based on the physical propey of the drug, It can bind to the agonist and prevent its action. Physiological antagonism describes the behavior of a substance that produces effects counteracting those of another substance using a mechanism that does not involve binding to the same receptor.