Chelating Agents for Heavy Metal Poisoning

Chelating Agents in Heavy Metal Poisoning

• Chelating agents work by forming stable, soluble complexes with heavy metals, which are then excreted by the kidneys, thereby removing the toxic metal from the body.

Chelating Agents for Specific Heavy Metals

• For Wilson's disease, penicillamine is recommended for removing excess copper.
• Chelation therapy is effective for treating lead, mercury, arsenic, and gold poisoning.

Administration of Chelating Agents

• Chelating agents are administered to patients to treat heavy metal poisoning, and the route of administration depends on the specific agent and patient needs.

Common Chelating Agents

• Dimercaprol (BAL) is the most commonly used chelating agent for treating heavy-metal poisoning.
• DMSA is used for the treatment of acute and chronic lead poisoning in both pediatric and adult populations.
• DMSA can also be used as an antidote for arsenic, lead, gold, and mercury poisoning.
• EDTA is a chelating agent that has an affinity for divalent and trivalent metals, forming stable, soluble complexes that are then excreted by the kidneys.
• EDTA competes with enzymes for the coordination of heavy metals and forms a chelated complex that is then excreted in the urine.

Properties of Chelating Agents

• DMSA contains a disulfide group that can be transformed in the body to a dithiol group.
• DMSA is indicated for the treatment of lead, arsenic, and mercury poisoning.
• EDTA is a modification of BAL containing two thiol groups and two carboxylic acid groups.
• DTPA forms strong complexes with lead, zinc, cadmium, manganese, iron, and mercury.

Specific Chelating Agents

• 'Edetate' refers to the calcium disodium salt of EDTA.
• '2,3-dimercapto-1-propanol' is the chemical name for BAL used for lead poisoning along with Disodium edetate.

Challenges of Chelation Therapy

• Cadmium poisoning is difficult to treat using chelation therapy due to the complexity of cadmium's chemical properties.