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Pronunciation
(dye mer KAP role)
Generic Available (U.S.)
No
Index Terms
Brand Names: U.S.
Pharmacologic Category
Use: Labeled Indications
Antidote to gold, arsenic (except arsine), or acute mercury poisoning (except nonalkyl mercury); adjunct to edetate CALCIUM disodium in acute lead poisoning
Pregnancy Risk Factor
C
Pregnancy Considerations
Animal reproduction studies have not been conducted. There are no adequate and well-controlled studies in pregnant women.Lead poisoning: Lead is known to cross the placenta in amounts related to maternal plasma levels. Prenatal lead exposure may be associated with adverse events such as spontaneous abortion, preterm delivery, decreased birth weight, and impaired neurodevelopment. Some adverse outcomes may occur with maternal blood lead levels <10 mcg/dL. In addition, pregnant women exposed to lead may have an increased risk of gestational hypertension. Consider chelation therapy in pregnant women with confirmed blood lead levels ≥45 mcg/dL (pregnant women with blood lead levels ≥70 mcg/dL should be considered for chelation regardless of trimester); consultation with experts in lead poisoning and high-risk pregnancy is recommended. Encephalopathic pregnant women should be chelated regardless of trimester (CDC, 2010).
Lactation
Excretion in breast milk unknown/use caution
Breast-Feeding Considerations
It is not known if dimercaprol is excreted in breast milk; however, it is not absorbed orally, which would limit the exposure to a nursing infant. When used for the treatment of lead poisoning, the amount of lead in breast milk may range from 0.6% to 3% of the maternal serum concentration. Women with confirmed blood lead levels ≥40 mcg/dL should not initiated breast-feeding; pumping and discarding breast milk is recommended until blood lead levels are <40 mcg/dL, at which point breast-feeding may resume (CDC, 2010). Calcium supplementation may reduce the amount of lead in breast milk.
Contraindications
Hepatic insufficiency (unless due to arsenic poisoning)
Warnings/Precautions
Concerns related to adverse effects:
• Nephrotoxicity: Potentially a nephrotoxic drug; use with caution in patients with oliguria. Keep urine alkaline to protect the kidneys (prevents dimercaprol-metal complex breakdown). Discontinue or use with extreme caution if renal insufficiency develops during treatment. Hemodialysis may be used to remove dimercaprol-metal chelate in patients with renal dysfunction
Special populations:
• Glucose 6-phosphate dehydrogenase deficiency: Use with caution in patients with glucose 6-phosphate dehydrogenase deficiency; may increase the risk of hemolytic anemia.
• Pediatrics: Fevers may occur in ~30% of children and may persist for the duration of therapy.
Disease related concerns:
• Lead poisoning: Investigate, identify, and remove sources of lead exposure prior to treatment; do not permit patients to re-enter the contaminated environment until lead abatement has been completed.
• Heavy metal poisoning: Primary care providers should consult experts in the chemotherapy of heavy metal toxicity before using chelation drug therapy.
Dosage form specific issues:
• Peanut oil: Product contains peanut oil; use with caution in patients with peanut allergy; medication for the treatment of hypersensitivity reactions should be available for immediate use.
Other warnings/precautions:
• Administration: Administer all injections deep I.M. at different sites; not for I.V. administration.
• Appropriate use: Not indicated for the treatment of iron, cadmium, or selenium poisoning; use in these patients may result in toxic dimercaprol-metal complexes.
Adverse Reactions
Frequency not always defined.
Cardiovascular: Chest pain, hypertension (dose related), tachycardia (dose related)
Central nervous system: Anxiety, fever (children ~30%), headache, nervousness
Dermatologic: Abscess
Gastrointestinal: Abdominal pain, burning sensation (lips, mouth, throat), nausea, salivation, throat irritation/pain, vomiting
Genitourinary: Burning sensation (penis)
Hematologic: Leukopenia (polymorphonuclear)
Local: Injection site pain
Neuromuscular & skeletal: Paresthesias (hand), weakness
Ocular: Blepharospasm, conjunctivitis, lacrimation
Renal: Acute renal insufficiency
Respiratory: Rhinorrhea, throat constriction
Miscellaneous: Diaphoresis
Metabolism/Transport Effects
None known.
Drug Interactions
Iron Salts: Dimercaprol may enhance the nephrotoxic effect of Iron Salts. Risk X: Avoid combination
Storage
Store at 20°C to 25°C (68°F to 77°F).
Mechanism of Action
Sulfhydryl group combines with ions of various heavy metals to form relatively stable, nontoxic, soluble chelates which are excreted in urine
Pharmacodynamics/Kinetics
Absorption: I.M.: Rapid; Oral: Not absorbed
Distribution: To all tissues including the brain
Metabolism: Hepatic; rapid to inactive metabolites
Time to peak, serum: 0.5-1 hour
Excretion: Urine
Dosage
Note: Premedication with a histamine H1 antagonist (eg, diphenhydramine) is recommended.
Children and Adults: Deep I.M.:
Arsenic or gold poisoning (acute, mild): 2.5 mg/kg every 6 hours for 2 days, then every 12 hours for 1 day, followed by once daily for 10 days
Arsenic or gold poisoning (acute, severe): 3 mg/kg every 4 hours for 2 days, then every 6 hours for 1 day, followed every 12 hours for 10 days
Mercury poisoning (acute): 5 mg/kg initially, followed by 2.5 mg/kg 1-2 times/day for 10 days
Lead poisoning: Note: For the treatment of high blood lead levels in children, the CDC recommends chelation treatment when blood lead levels are >45 mcg/dL (CDC, 2002); however, dimercaprol is only recommended for use (in combination with edetate CALCIUM disodium) in children whose blood lead levels are >70 mcg/dL or in children with lead encephalopathy (AAP, 2005; Chandran, 2010). In adults, available guidelines recommend chelation therapy with blood lead levels >50 mcg/dL and significant symptoms; chelation therapy may also be indicated with blood lead levels ≥100 mcg/dL and/or symptoms (Kosnett, 2007).
Blood lead levels ≥70 mcg/dL, symptomatic lead poisoning, or lead encephalopathy (in conjunction with edetate CALCIUM disodium): 4 mg/kg every 4 hours for 2-7 days; duration of therapy of at least 3 days is recommended by some experts (Chandran, 2010). Note: Begin treatment with edetate CALCIUM disodium with the second dimercaprol dose.
Administration: I.M.
Administer all injections by deep I.M. injection. Rotate injection sites. Keep urine alkaline to protect renal function. When used in the treatment of lead poisoning, administer in a separate site from edetate CALCIUM disodium.
Monitoring Parameters
Renal function, urine pH, infusion-related reactions
For lead poisoning: Blood lead levels (baseline and 7-21 days after completing chelation therapy); hemoglobin or hematocrit, iron status, free erythrocyte protoporphyrin or zinc protoporphyrin; neurodevelopmental changes
For arsenic poisoning: Urine arsenic concentration
Test Interactions
Iodine I131 thyroidal uptake values may be decreased
Dental Health: Effects on Dental Treatment
No significant effects or complications reported
Dental Health: Vasoconstrictor/Local Anesthetic Precautions
No information available to require special precautions
Mental Health: Effects on Mental Status
May cause nervousness
Mental Health: Effects on Psychiatric Treatment
May produce neutropenia; use caution with clozapine and carbamazepine
Dosage Forms
Excipient information presented when available (limited, particularly for generics); consult specific product labeling.
Injection, oil:
BAL in Oil®: 100 mg/mL (3 mL) [contains benzyl benzoate, peanut oil]
References
Cantilena LR Jr and Klaassen CD, “The Effect of Chelating Agents on the Excretion of Endogenous Metals,” Toxicol Appl Pharmacol, 1982, 63(3):344-50.
Centers for Disease Control and Prevetion (CDC), Guidelines for the Identification and Management of Lead Exposure in Pregnant and Lactating Women, Atlanta: CDC; 2010.
Centers for Disease Control and Prevention (CDC), Managing Elevated Blood Lead Levels Among Young Children: Recommendations from the Advisory Committee on Childhood Lead Poisoning Prevention, Atlanta: CDC; 2002.
Centers for Disease Control and Prevention (CDC), “Interpreting and Managing Blood Lead Levels <10 microg/dL in Children and Reducing Childhood Exposures to Lead: Recommendations of CDC's Advisory Committee on Childhood Lead Poisoning Prevention,” MMWR Recomm Rep, 2007, 56(RR-8):1-16.
Chandran L and Cataldo R, “Lead Poisoning: Basics and New Developments,” Pediatr Rev, 2010, 31(10):399-406.
Gardella C, “Lead Exposure in Pregnancy: A Review of the Literature and Argument for Routine Prenatal Screening,” Obstet Gynecol Surv, 2001, 56(4):231-8.
Kosnett MJ, “Chelation for Heavy Metals (Arsenic, Lead, and Mercury): Protective or Perilous?” Clin Pharmacol Ther, 2010, 88(3):412-15.
Kosnett MJ, “Unanswered Questions in Metal Chelation,” J Toxicol Clin Toxicol, 1992, 30(4):529-47.
Kosnett MJ, Wedeen RP, Rothenberg SJ, et al, “Recommendations for Medical Management of Adult Lead Exposure,” Environ Health Perspect, 2007, 115(3):463-71.
“Lead Exposure in Children: Prevention, Detection, and Management. American Academy of Pediatrics Committee on Environmental Health,” Pediatrics, 2005, 116(4):1036-46.
Shannon M, “Severe Lead Poisoning in Pregnancy,” Ambul Pediatr, 2003, 3(1):37-9.
International Brand Names
Lexi-Comp.com
Last full review/revision February 2012
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