Lewisite

CAS RN: 541-25-3

Treatment Overview

0.4.2 ORAL EXPOSURE
  • A) Do NOT induce emesis.
  • B) DILUTION: If no respiratory compromise is present, administer milk or water as soon as possible after ingestion. Dilution may only be helpful if performed in the first seconds to minutes after ingestion. The ideal amount is unknown; no more than 8 ounces (240 mL) in adults and 4 ounces (120 mL) in children is recommended to minimize the risk of vomiting (Caravati, 2004).
  • C) Consider insertion of a small, flexible nasogastric tube to aspirate gastric contents soon after a significant ingestion. The risk of worsening mucosal injury must be weighed against the potential benefit of removal of this systemic toxin.
  • D) ACTIVATED CHARCOAL: Administer charcoal as a slurry (240 mL water/30 g charcoal). Usual dose: 25 to 100 g in adults/adolescents, 25 to 50 g in children (1 to 12 years), and 1 g/kg in infants less than 1 year old.
  • E) Monitor serum electrolytes and administer replacement therapy as indicated.
  • F) Chelation with dimercaprol (BAL) or succimer (DMSA) or DMPS should be initiated in patients exhibiting systemic effects or patients with large areas of dermal burns or patients with liquid Lewisite contamination over greater than 5% of their body surface area. The 24-hour urine arsenic level should be less than 50 mcg/L before stopping chelation therapy. Organic dietary arsenic (normally found in seafood) may account for some urinary arsenic, and when in question, it should be speciated to determine organic and inorganic concentrations. Furthermore, any dietary seafood should be avoided during therapy because of this reason.
  • G) HYPOTENSION: Infuse 10 to 20 mL/kg isotonic fluid. If hypotension persists, administer dopamine (5 to 20 mcg/kg/min) or norepinephrine (ADULT: begin infusion at 0.5 to 1 mcg/min; CHILD: begin infusion at 0.1 mcg/kg/min); titrate to desired response.
0.4.3 INHALATION EXPOSURE
  • A) INHALATION: Move patient to fresh air. Monitor for respiratory distress. If cough or difficulty breathing develops, evaluate for respiratory tract irritation, bronchitis, or pneumonitis. Administer oxygen and assist ventilation as required. Treat bronchospasm with an inhaled beta2-adrenergic agonist. Consider systemic corticosteroids in patients with significant bronchospasm.
  • B) Monitor serum electrolytes and administer replacement therapy as indicated.
  • C) Chelation with dimercaprol (BAL) or succimer (DMSA) or DMPS should be initiated in patients exhibiting systemic effects or patients with large areas of dermal burns or patients with liquid Lewisite contamination over greater than 5% of their body surface area. The 24-hour urine arsenic level should be less than 50 mcg/L before stopping chelation therapy. Organic dietary arsenic (normally found in seafood) may account for some urinary arsenic, and when in question, it should be speciated to determine organic and inorganic concentrations. Furthermore, any dietary seafood should be avoided during therapy because of this reason.
  • D) ACUTE LUNG INJURY: Maintain ventilation and oxygenation and evaluate with frequent arterial blood gases and/or pulse oximetry monitoring. Early use of PEEP and mechanical ventilation may be needed.
  • E) HYPOTENSION: Infuse 10 to 20 mL/kg isotonic fluid. If hypotension persists, administer dopamine (5 to 20 mcg/kg/min) or norepinephrine (ADULT: begin infusion at 0.5 to 1 mcg/min; CHILD: begin infusion at 0.1 mcg/kg/min); titrate to desired response.
  • F) Hemodialysis should be performed in the presence of renal failure.
0.4.4 EYE EXPOSURE
  • A) DECONTAMINATION: Remove contact lenses and irrigate exposed eyes with copious amounts of room temperature 0.9% saline or water for at least 15 minutes. If irritation, pain, swelling, lacrimation, or photophobia persist after 15 minutes of irrigation, the patient should be seen in a healthcare facility.
  • B) BAL - If applied within a few minutes of contact, it may prevent permanent damage.
  • C) All patients with significant eye exposure should be carefully monitored for possible development of systemic signs and symptoms. Follow treatment recommendations in the INHALATION EXPOSURE section where appropriate.
0.4.5 DERMAL EXPOSURE
  • A) OVERVIEW
    • 1) Prompt decontamination is extremely important. Any exposed skin (as well as exposed clothes) should be irrigated/washed with a 5% solution of sodium hypochlorite (diluted liquid household bleach), as soon as possible (preferably within one minute). Wash contaminated skin with soap and water afterwards. Topical 5% BAL ointment or solution may decrease blistering effects.
    • 2) DECONTAMINATION: Remove contaminated clothing and jewelry and place them in plastic bags. Wash exposed areas with soap and water for 10 to 15 minutes with gentle sponging to avoid skin breakdown. A physician may need to examine the area if irritation or pain persists (Burgess et al, 1999).
    • 3) Treat dermal irritation or burns with standard topical therapy. Patients developing dermal hypersensitivity reactions may require treatment with systemic or topical corticosteroids or antihistamines.
    • 4) Monitor serum electrolytes and administer replacement therapy as indicated.
    • 5) Chelation with dimercaprol (BAL) or succimer (DMSA) or DMPS should be initiated in patients exhibiting systemic effects or patients with large areas of dermal burns or patients with liquid Lewisite contamination over greater than 5% of their body surface area. The 24-hour urine arsenic level should be less than 50 mcg/L before stopping chelation therapy. Organic dietary arsenic (normally found in seafood) may account for some urinary arsenic, and when in question, it should be speciated to determine organic and inorganic concentrations. Furthermore, any dietary seafood should be avoided during therapy because of this reason.
    • 6) COOLING - In one animal study, it was determined that cooling of Lewisite-exposed skin for 2 hours, followed by 1 hour of DMSA topical application was effective in reducing skin injury compared to either therapy alone.
    • 7) HYPOTENSION: Infuse 10 to 20 mL/kg isotonic fluid. If hypotension persists, administer dopamine (5 to 20 mcg/kg/min) or norepinephrine (ADULT: begin infusion at 0.5 to 1 mcg/min; CHILD: begin infusion at 0.1 mcg/kg/min); titrate to desired response.
    • 8) Hemodialysis should be performed in the presence of renal failure.
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