British anti-Lewisite

British Anti-Lewisite

British Anti-Lewisite (BAL), also known as dimercaprol, is a chelating agent developed during World War II as an antidote to the chemical warfare agent Lewisite. It is primarily used in the treatment of heavy metal poisoning, including arsenic, mercury, and lead.

History

British Anti-Lewisite was developed by British biochemists at the University of Oxford during World War II. The need for an antidote arose due to the threat of chemical warfare agents like Lewisite, which is an arsenic-containing compound. The development of BAL was a significant advancement in the field of toxicology and pharmacology.

Chemical Structure and Properties

BAL is a colorless or pale yellow oily liquid with a strong mercaptan odor. Its chemical formula is C₃H₈OS₂, and it is a bidentate ligand, meaning it can form two bonds with a metal ion. This property allows it to effectively bind to heavy metals, forming stable, non-toxic complexes that can be excreted from the body.

Mechanism of Action

The primary mechanism of action of British Anti-Lewisite is its ability to chelate heavy metals. BAL contains two thiol (sulfhydryl) groups that can bind to metal ions, such as arsenic, mercury, and lead. By forming a complex with these metals, BAL prevents them from interacting with biological molecules, thereby reducing their toxicity.

Medical Uses

BAL is used in the treatment of:

• Arsenic poisoning: BAL is effective in chelating arsenic, which is a component of Lewisite and other toxic compounds.
• Mercury poisoning: It can bind to mercury ions, reducing their harmful effects.
• Lead poisoning: Although not the first-line treatment, BAL can be used in cases of severe lead poisoning.

Administration and Dosage

BAL is administered via intramuscular injection. The dosage and duration of treatment depend on the severity of the poisoning and the specific metal involved. It is important to monitor patients for potential side effects, which can include hypertension, tachycardia, and pain at the injection site.

Side Effects and Precautions

Common side effects of BAL include:

• Hypertension
• Tachycardia
• Nausea and vomiting
• Pain at the injection site

Patients with peanut allergies should avoid BAL, as it is formulated in a peanut oil base. Additionally, BAL should be used with caution in patients with renal impairment.

Also see

• Lewisite
• Chelation therapy
• Heavy metal poisoning
• Arsenic poisoning
• Mercury poisoning
• Lead poisoning