Ammonium Nitrate

CAS RN:6484-52-2

Treatment Overview

0.4.2 ORAL EXPOSURE
  • A) MANAGEMENT OF MILD TO MODERATE TOXICITY
    • 1) Treatment is symptomatic and supportive. Mild to moderate hypotension is treated by placing the patient in a supine position. Infusion of IV crystalloid is usually sufficient to reverse nitrate induced hypotension.
  • B) MANAGEMENT OF SEVERE TOXICITY
    • 1) Treatment is symptomatic and supportive. Treat hypotension with IV fluids. Vasopressors are rarely required. Treat symptomatic methemoglobinemia with methylene blue.
  • C) DECONTAMINATION
    • 1) PREHOSPITAL: Remove patients from the exposure and to fresh air. Administer oxygen to symptomatic patients.
    • 2) HOSPITAL: Decontamination is unlikely to be of assistance as these agents are rapidly absorbed.
  • D) AIRWAY MANAGEMENT
    • 1) Nitrates may cause airway irritation but it is rare for patients to require intubation.
  • E) ANTIDOTE
    • 1) None
  • F) HYPOTENSIVE EPISODE
    • 1) Hypotension after nitrate overdose is secondary to venodilation. Keep the patient supine; primary therapy is restoring intravascular volume with fluid. Administer 10 to 20 mL/kg 0.9% saline. Central venous pressure monitoring may be useful to guide further fluid therapy. Vasopressors should be used only in patients who do not respond to adequate fluid resuscitation.
  • G) METHEMOGLOBINEMIA
    • 1) Initiate oxygen therapy. Treat with methylene blue if patient is symptomatic (usually at methemoglobin concentrations greater than 20% to 30% or at lower concentrations in patients with anemia, underlying pulmonary or cardiovascular disease). METHYLENE BLUE: INITIAL DOSE/ADULT OR CHILD: 1 mg/kg IV over 5 to 30 minutes; a repeat dose of up to 1 mg/kg may be given 1 hour after the first dose if methemoglobin levels remain greater than 30% or if signs and symptoms persist. NOTE: Methylene blue is available as follows: 50 mg/10 mL (5 mg/mL or 0.5% solution) single-dose ampules and 10 mg/1 mL (1% solution) vials. Additional doses may sometimes be required. Improvement is usually noted shortly after administration if diagnosis is correct. Consider other diagnoses or treatment options if no improvement has been observed after several doses. If intravenous access cannot be established, methylene blue may also be given by intraosseous infusion. Methylene blue should not be given by subcutaneous or intrathecal injection. NEONATES: DOSE: 0.3 to 1 mg/kg.
  • H) ENHANCED ELIMINATION
    • 1) Nitrates are removed by dialysis but it is unlikely to be used clinically as most cases reverse relatively quickly.
  • I) PATIENT DISPOSITION
    • 1) HOME CRITERIA: Asymptomatic patients with inadvertent exposure may be observed at home.
    • 2) OBSERVATION CRITERIA: Observe patients with symptomatic hypotension until symptoms resolve. Observe patients treated with methylene blue for 6 hours.
    • 3) ADMISSION CRITERIA: Admit patients with persistent hypotension or end organ ischemia. Admit patients with methemoglobinemia and evidence of hemolysis or patients requiring a second treatment with methylene blue.
    • 4) CONSULT CRITERIA: Consult a medical toxicologist for patients who have persistent symptoms, require treatment with methylene blue or who have G6PD deficiency.
  • J) PITFALLS
    • 1) It is important to be aware that methemoglobinemia may recur.
  • K) TOXICOKINETICS
    • 1) Nitrates are highly and rapidly absorbed. Approximately 60% are excreted in urine and approximately 10% of a dose is converted to nitrites in the gastrointestinal tract, which enhances toxic effects.
  • L) PREDISPOSING CONDITIONS
    • 1) Patients with G6PD deficiency may develop hemolysis secondary to methemoglobinemia and may not respond to methylene blue therapy. Infants younger than 4 months of age are at increased risk for methemoglobinemia from nitrate contaminated ground water.
  • M) DIFFERENTIAL DIAGNOSIS
    • 1) Includes nitrite exposure or exposure to other vasodilators or oxidizing agents.
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.
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.
0.4.5 DERMAL EXPOSURE
  • A) OVERVIEW
    • 1) 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).
    • 2) Some chemicals can produce systemic poisoning by absorption through intact skin. Carefully observe patients with dermal exposure for the development of any systemic signs or symptoms and administer symptomatic treatment as necessary.
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