Which antidote is used for mercury poisoning?

Dimercaprol is the appropriate antidote for mercury poisoning because it is a chelating agent specifically effective in binding to heavy metals, including mercury. By forming stable complexes with mercury ions, dimercaprol helps to facilitate their excretion from the body, thereby reducing the toxic burden of mercury.

Mercury can be particularly harmful to various organ systems, and its toxicity necessitates rapid treatment. Dimercaprol has a sulfur-containing structure that is capable of forming bonds with the mercury, which is crucial for effectively detoxifying and eliminating it from the body. This makes it the first-line treatment in cases of acute mercury poisoning.

Other agents listed do not specifically target mercury. For instance, fomepizole is primarily an alcohol dehydrogenase inhibitor used in methanol or ethylene glycol poisoning. Penicillamine can be used to treat copper poisoning and certain other heavy metal toxicities, but it is not the first choice for mercury. Deferoxamine is used for iron toxicity and does not have a chelating action on mercury. Therefore, in the case of mercury poisoning, dimercaprol is the most suitable antidote.