Arsenic, Elemental

CAS RN:7440-38-2

Treatment Overview

0.4.2 ORAL EXPOSURE
  • A) MANAGEMENT OF MILD TO MODERATE TOXICITY
    • 1) Fluid resuscitation should be initiated immediately, but care must be taken to recognize pulmonary and cerebral edema when present. When a significant acute ingestion is confirmed, chelation therapy should be initiated immediately prior to laboratory confirmation. This will minimize time delay to treatment associated with prolonged laboratory result turn around. In chronic toxicity, the decision to chelate must be based upon patient condition and laboratory evaluation.
  • B) MANAGEMENT OF SEVERE TOXICITY
    • 1) Aggressive life support measures should be instituted immediately. Anti-arrhythmic medications that prolong the QTc should be avoided. In severely ill patients, combined therapy with both BAL and an oral agent should be considered. If renal failure exists, the dose of BAL should be decreased after the loading dose.
    • 2) INHALATION EXPOSURE: Inhalation is the most common exposure in arsenic workers. OSHA has set an "action level" of 5 mcg/m(
    • 3) of inorganic arsenic in the air over an 8-hour period. Initial treatment should be to remove the patient from the exposure and refer the patient to an occupational specialist for 24-hour urine collection. The decision to chelate will depend upon the patient's clinical status and urine arsenic concentration.
    • 3) DERMAL EXPOSURE: Occasionally arsenic can cause a contact dermatitis or an exfoliative rash. Wash the area thoroughly and avoid further dermal contact. Topical steroid creams may decrease inflammation in these cases.
    • 4) EYE EXPOSURE: Copious irrigation and ophthalmology follow-up.
  • C) DECONTAMINATION
    • 1) PREHOSPITAL: Remove the contaminated clothing and wash the patient thoroughly.
    • 2) HOSPITAL: Activated charcoal does not bind arsenic well. Gastric lavage and whole bowel irrigation should be considered for confirmed significant ingestions.
  • D) AIRWAY MANAGEMENT
    • 1) Should be considered for patients with severe CNS depression at risk of aspiration.
  • E) ANTIDOTE
    • 1) For patients with severe poisoning or a history of a large exposure, initial chelation should be with a parenteral chelator (intramuscular BAL or intravenous unithiol). When the patient is improving and able to tolerate oral medication, therapy can be switched to an oral chelator with no waiting period in between treatments. BAL is administered by deep intramuscular injection 3 to 5 mg/kg/dose IM every 4 to 6 hours. The dose and frequency depend on the degree of toxicity seen. Higher doses of BAL invariably cause adverse effects. SUCCIMER: Should be used as soon as the patient is improving and able to tolerate oral medication. DOSE: 10 mg/kg every 8 hours for 5 days, then decrease dosing to every 12 hours for 14 days. It may be more effective and causes fewer side effects than BAL. Chelation therapy should be stopped when the urinary arsenic level falls below 50 mcg per 24 hours. UNITHIOL (2,3-dimercaptopropanol-sulfonic acid, DMPS) is available in Europe and through compounding pharmacies in the United States. It is a water-soluble analog of BAL, and can be given orally or parenterally. Unithiol is dosed as follows: IV: Day one 250 mg/kg every 3 to 4 hours, day two 250 mg every 4 to 6 hours, day three 250 mg every 6 to 8 hours, day four 250 mg every 8 to 12 hours, days five and six: 250 mg every 8 to 24 hours. Depending on the patient's clinical status, therapy may be changed to the oral route after the fifth day: 100 to 300 mg 3 times daily. ORAL: Initially 1200 mg to 2400 mg every 24 hours divided (100 mg or 200 mg every 2 hours), reduce to 100 mg to 300 mg every 8 hours as tolerated. Patients should be treated for 14 days or until there is no arsenic detected in the urine.
  • F) VENTRICULAR DYSRHYTHMIAS
    • 1) Institute continuous cardiac monitoring, obtain an ECG, and administer oxygen. Evaluate for hypoxia, acidosis, and electrolyte disorders. Lidocaine and amiodarone are generally first line agents for stable monomorphic ventricular tachycardia, particularly in patients with underlying impaired cardiac function. Because arsenic can cause torsades de pointes and QTc prolongation, amiodarone should only be used with extreme caution. Unstable rhythms require immediate cardioversion.
  • G) TORSADES DE POINTES
    • 1) Treat with magnesium; atrial overdrive pacing may also be indicated. Correct electrolyte abnormalities.
  • H) ENHANCED ELIMINATION
    • 1) Arsenic is poorly dialyzable. Hemodialysis should only be considered for arsenic toxicity accompanied by renal failure.
  • I) PATIENT DISPOSITION
    • 1) ADMISSION CRITERIA: All patients with acute arsenic toxicity should be admitted.
    • 2) CONSULT CRITERIA: Consult a medical toxicologist and/or poison center for all potentially significant arsenic exposures.
  • J) PITFALLS
    • 1) Failure to consider arsenic poisoning in patients with prolonged gastrointestinal illness and cardiac conduction abnormalities. Failure to remove fish or other arsenic sources from the diet prior to testing urine arsenic levels.
  • K) DIFFERENTIAL DIAGNOSIS
    • 1) Infectious gastroenteritis may have a similar clinical presentation, though arsenic toxicity usually lasts longer and has more multi-organ system involvement. Toxic plant and mushroom ingestion may lead to a severe gastritis though most lack the systemic toxicity seen with arsenic. Theophylline overdose may have a similar presentation though diarrhea is not as predominant a feature as it is with arsenic poisoning.
0.4.3 INHALATION EXPOSURE
  • A) Inhalation is the most common exposure in arsenic workers. OSHA has set an "action level" of 5 mcg/m(
    • 3) of inorganic arsenic in the air over an 8-hour period. Initial treatment should be to remove the patient from the exposure and refer the patient to an occupational specialist for 24-hour urine collection. The decision to chelate will depend upon the patient's clinical status and urine arsenic concentration.
0.4.4 EYE EXPOSURE
  • A) Copious irrigation and ophthalmology follow-up.
0.4.5 DERMAL EXPOSURE
  • A) OVERVIEW
    • 1) Occasionally arsenic can cause a contact dermatitis or an exfoliative rash. Wash the area thoroughly and avoid further dermal contact. Topical steroid creams may decrease inflammation in these cases.
Find more information on this substance at: Hazardous Substances Data Bank , TOXNET , PubMed