Dimercaprol

Information about Dimercaprol

Dimercaprol, or British anti-Lewisite (BAL), is a parenterally administered heavy metal chelating agent that is used to treat arsenic, gold, copper and mercury poisoning. 

Liver safety of Dimercaprol

Dimercaprol has not been associated with serum enzyme elevations during therapy or with cases of clinically apparent liver injury with jaundice, but its general use has been quite limited.

Mechanism of action of Dimercaprol

Dimercaprol (dye” mer cap’ rol) is a parenterally administered heavy metal chelating agent which has been used to treat arsenic, copper, gold, lead and mercury poisoning as well as severe cases of Wilson disease.  Dimercaprol was developed at Oxford University during World War II as a means of treating and reversing poisoning from Lewisite, an arsenical gas used in chemical warfare (and thus initially called British anti-Lewisite or BAL).  Dimercaprol is a simple propranol molecule with two sulfhydryl groups that acts by binding heavy metals, and thus competing and blocking the binding of the toxic metals to sulfhydryl containing metabolic enzymes.  Dimercaprol binds mercury, lead, copper, gold and arsenic, and its major current indications are for poisoning with arsenic, gold and mercury and, in combination with EDTA-calcium, acute lead poisoning. 

Copper chelation

In addition, dimercaprol has been used to chelate copper in patients with Wilson disease, but now has been replaced by better tolerated oral chelating agents such as penicillamine and trientine.  Dimercaprol is occasionally used in the initial treatment of severe, symptomatic Wilson disease, but generally for a short time only. 

Dosage and administration for Dimercaprol

Dimercaprol is available in solution in oil in ampules of 300 mg (100 mg/mL) generically and under the name BAL.  The recommended dose and regimen vary by indication, but are in the range of 2.5 to 5 mg/kg two to five times daily, given by deep intramuscular injection for 2 to 10 days.  Dimercaprol is not indicated and may be harmful in iron, cadmium and selenium poisoning.  Side effects include injection site reactions, local pain and sterile abscesses as well as systemic symptoms such as nausea, vomiting, headache, dizziness, spasms, sweating, excessive lacrimation or salivation, and skin or body tingling, burning and pain.  Rare, but potentially severe adverse events include seizures, stupor and coma.

Wilson disease

Wilson disease is an inherited abnormality of copper metabolism that leads to excess copper accumulation and injury to liver, brain and other organs.  The metabolic defect in Wilson disease is caused by mutations in ATPase7B, a hepatic enzyme responsible for transmembrane transport and excretion of copper into the bile.  The metabolic defect leads to accumulation of free copper in liver and blood and secondarily in other organs, particularly brain and kidney.  The disease usually presents in childhood or adolescence with neurologic syndromes, signs of advanced liver disease and hemolytic anemia.  If untreated it is invariably fatal, death being from progressive neurologic disease or acute or chronic liver failure.  Therapy of Wilson disease is usually based upon copper chelation, but limitation of copper in the diet and approaches to inhibiting copper absorption can also be important.

List of Dimercaprol

Copper chelating agents available in the United States include penicillamine, trientine and dimercaprol.  These agents lower blood and tissue copper levels and, when given chronically, prevent copper accumulation and injury in Wilson disease.  Penicillamine is considered the first line therapy of Wilson disease, but is often limited by its unique side effects that can be severe and may be dose limiting.  Trientine is a second line agent and is less effective than penicillamine in chelating copper, but it has fewer serious side effects and is generally well tolerated.  Both of these agents are given orally.  Dimercaprol (also known as British anti-Lewisite or BAL) was the initial copper chelating agent developed for Wilson disease, but it requires parenteral administration and has frequent serious adverse effects. 

Dimercaprol is currently rarely used for Wilson disease and generally only in conjunction with oral copper chelating agents, for a short period of time, and in patients with severe symptomatic disease. 

Zinc and Wilson]s disease

Zinc is also useful in managing Wilson disease and acts by inhibition of copper absorption, rather than chelation of excess copper in tissue or the circulation.  Zinc has been used as a first line therapy, but is currently recommended largely as maintenance therapy once chelation of excess copper has been accomplished.

Liver safety of Dimercaprol

Among the drugs used for Wilson disease, only penicillamine has been linked to cases of clinically apparent liver injury.  Penicillamine has been linked to cases of acute, immunoallergic hepatitis which is likely due to hypersensitivity.

Arsenic Chelators

• Dimercaprol

Copper Chelators (for Wilson Disease)

• Dimercaprol
• Penicillamine
• Trientine
• Zinc

Iron Chelators

• Deferasirox
• Deferiprone
• Deferoxamine

Lead Chelators

• Dimercaprol
• EDTA
• Succimer

Mercury Chelators

• Dimercaprol

• Dailymed label info on Dimercaprol
• FDA Dimercaprol

Dimercaprol Resources
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