Ammonium Nitrate

CAS RN:6484-52-2

Health Effects

0.2.1 SUMMARY OF EXPOSURE
  • 0.2.1.1 ACUTE EXPOSURE
    • A) USES: Nitrates occur naturally in many plants and are used as fertilizer. Ammonium nitrate is used in instant cooling packets. Well water may become contaminated with nitrates from fertilizers or natural causes. Nitrate-based medications are used as vasodilators (including isosorbide, nitroprusside and nitroglycerin) and are covered in separate managements.
    • B) PHARMACOLOGY: Nitrates cause vasodilation by being converted to nitrites and eventually to nitric oxide.
    • C) TOXICOLOGY: The toxicity of nitrates is due to in vivo conversion to nitrites. Excessive vasodilation may cause hypotension and hypoperfusion. Nitrates are potent oxidizers and can produce methemoglobinemia and hemolysis.
    • D) EPIDEMIOLOGY: Nitrate exposures are uncommon. Severe effects are rare except in cases where large exposures to fertilizers produces high methemoglobin concentrations.
    • E) MILD TO MODERATE TOXICITY: Overdose generally causes orthostatic hypotension and reflex tachycardia. Headache, nausea, and vomiting are also fairly common. Syncope, dizziness or lightheadedness, diaphoresis, and flushed skin may develop. Mild methemoglobinemia generally does not cause symptoms. Cyanosis and dyspnea develop with moderate methemoglobinemia. Nitrates can be irritating to the gastrointestinal tract, eyes, and mucous membranes.
    • F) SEVERE TOXICITY: In severe poisonings, unconsciousness, dizziness, fatigue, shortness of breath, and hypotension may develop. Hypotension, dysrhythmias, myocardial ischemia, seizures, confusion, coma, metabolic acidosis, and death may occur with methemoglobin concentrations of greater than 50%.
0.2.3 VITAL SIGNS
  • 0.2.3.1 ACUTE EXPOSURE
    • A) Orthostatic hypotension and tachycardia are common. Frank hypotension and bradycardia are possible.
0.2.4 HEENT
  • 0.2.4.1 ACUTE EXPOSURE
    • A) Nitrate salts may be irritating to the eyes and mucous membranes.
0.2.5 CARDIOVASCULAR
  • 0.2.5.1 ACUTE EXPOSURE
    • A) Nitrite-induced peripheral vasodilatation may occur after nitrates have been converted to nitrites in vivo. Orthostatic hypotension and tachycardia are common. Hypotension, decreased peripheral vascular resistance, cardiovascular collapse, or bradycardia occur less often.
    • B) Dysrhythmias including atrial fibrillation, frequent ventricular premature beats, and bigeminy may occur with severe poisoning. Ischemia may also occur with severe poisoning.
    • C) Coronary vasospasm and ischemia have been reported after abrupt withdrawal from chronic occupational nitrate exposure.
0.2.6 RESPIRATORY
  • 0.2.6.1 ACUTE EXPOSURE
    • A) Once nitrates have been converted to nitrites, cyanosis and dyspnea may develop due to methemoglobin formation.
0.2.7 NEUROLOGIC
  • 0.2.7.1 ACUTE EXPOSURE
    • A) Headache is a common symptom once nitrates have been converted to nitrites. Nitrates themselves produce few neurologic symptoms. Coma has been reported with severe poisoning.
0.2.8 GASTROINTESTINAL
  • 0.2.8.1 ACUTE EXPOSURE
    • A) Nausea and vomiting are the first signs to be noted following ingestion.
    • B) Diarrhea and abdominal pain are also noted. Gastrointestinal inflammation has been seen at autopsy.
0.2.11 ACID-BASE
  • 0.2.11.1 ACUTE EXPOSURE
    • A) Falsely elevated CO2 levels with a negative anion gap were associated with elevated potassium levels secondary to ingestion of potassium nitrate.
    • B) Elevated anion gap acidosis may occur.
0.2.13 HEMATOLOGIC
  • 0.2.13.1 ACUTE EXPOSURE
    • A) Methemoglobinemia may be noted, and is associated with cyanosis that does not respond to oxygen therapy.
0.2.20 REPRODUCTIVE HAZARDS
  • A) ISOSORBIDE DINITRATE, ISOSORBIDE DINITRATE AND HYDRALAZINE COMBINATION, and NITROGLYCERIN are classified as US FDA Pregnancy Category C. ISOSORBIDE MONONITRATE is classified as Pregnancy Category B. Nitrate-based medications (eg, isosorbide mononitrate and dinitrate, nitroglycerin, and sodium nitroprusside) are typically used as vasodilators. Please refer to the NITROGLYCERIN and SODIUM NITROPRUSSIDE documents for more information on these agents.
0.2.21 CARCINOGENICITY
  • 0.2.21.2 HUMAN OVERVIEW
    • A) An increased incidence of stomach cancer was seen in one group of workers with occupational exposure to nitrate fertilizer.
0.2.22 GENOTOXICITY
  • A) At the time of this review, no data were available to assess the mutagenic or genotoxic potential of this agent.
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