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Pronunciation
(dye mer KAP role)
U.S. Brand Names
Index Terms
Generic Available
No
Pharmacologic Category
Use: Labeled Indications
Antidote to gold, arsenic (except arsine), or acute mercury poisoning (except nonalkyl mercury); adjunct to edetate CALCIUM disodium in 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: Following maternal occupational exposure, lead was found to cross the placenta in amounts related to maternal plasma levels. Possible outcomes of maternal lead exposure >10 mcg/dL include spontaneous abortion, postnatal developmental delay, and reduced birth weight. Chelation therapy during pregnancy is for maternal benefit only and should be limited to the treatment of severe, symptomatic lead poisoning.
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. Calcium supplementation may reduce the amount of lead in breast milk.
Contraindications
Hepatic insufficiency (unless due to arsenic poisoning); iron, cadmium, or selenium 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 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 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.
• Heavy metal poisoning: Primary care providers should consult experts in 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.
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
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: Rapidly hepatic 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.:
Mild arsenic or gold poisoning: 2.5 mg/kg every 6 hours for 2 days, then every 12 hours for 1 day, followed by once daily for 10 days
Severe arsenic or gold poisoning: 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: 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). Combination parenteral therapy is indicated when blood lead levels are ?70 mcg/dL, or patients are symptomatic (AAP, 2005). 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).
Lead encephalopathy (in conjunction with edetate CALCIUM disodium): Dimercaprol 4 mg/kg (75 mg/m2) loading dose, followed by dimercaprol 4 mg/kg (75 mg/m2) every 4 hours for 2-7 days (edetate CALCIUM disodium is not administered with the loading dose; begin edetate CALCIUM disodium with the second dose)
Symptomatic lead poisoning or blood lead levels ?70 mcg/dL (in conjunction with edetate CALCIUM disodium): Dimercaprol 4 mg/kg (75 mg/m2) loading dose, followed by dimercaprol 3 mg/kg/dose (50 mg/m2) every 4 hours for 2-7 days (edetate CALCIUM disodium is not administered with the loading dose; begin edetate CALCIUM disodium with the second dose)
Administration: I.M.
Administer all injections deep I.M. at different 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
Test Interactions
Iodine 131I 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 and 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 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.
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, “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 August 2008
Content last modified August 2008
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