Question
Write briefly on chelating agents.
Q15 4 marks Short Answers ★ ✓
Answer
Chelating agents bind metal ions to form stable, water-soluble complexes that are readily excreted, used as antidotes in heavy metal poisoning.
By metal :
Lead : EDTA (edetate calcium disodium), Dimercaprol (severe cases), Succimer (DMSA — oral, avoids dimercaprol’s painful IM injection, particularly useful in children).Iron : Deferoxamine (parenteral).Copper (Wilson’s disease): Penicillamine, Trientine.Arsenic/mercury/gold : Dimercaprol (British anti-Lewisite, BAL).
Mechanism : form stable ring-shaped complexes with the metal ion, converting a toxic, tissue-bound form into an inert, water-soluble form excreted mainly by the kidney.
Adverse effects : hypotension and injection-site pain (dimercaprol), hypocalcemia (EDTA if not given as the calcium-disodium salt), nephrotoxicity, and depletion of essential trace metals with prolonged use.
1 Chelating Agents
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