Nitroglycerin

CAS RN:55-63-0

Treatment Overview

0.4.2 ORAL EXPOSURE
  • A) MANAGEMENT OF MILD TO MODERATE TOXICITY
    • 1) Administer IV fluids for hypotension.
  • B) MANAGEMENT OF SEVERE TOXICITY
    • 1) Administer activated charcoal (GI decontamination should be performed only in patients who can protect their airway or who are intubated). Severe hypotension may develop and require intravenous fluids and vasopressors. After inhalation exposure, move patient to fresh air and monitor for respiratory distress.
  • C) DECONTAMINATION
    • 1) PREHOSPITAL: Administer activated charcoal if recent, substantial ingestion of a sustained-release formulation, and the patient is able to protect their airway. If dermal exposure, remove nitroglycerin ointment/paste or patch and wash the exposed area thoroughly with soap and water. GI decontamination is not effective after sublingual exposure and is unlikely to be useful for regular release formulations because of rapid absorption and a short half-life.
    • 2) HOSPITAL: Administer activated charcoal if recent, substantial ingestion of a sustained-release formulation, and patient able to protect airway. If dermal exposure, remove nitroglycerin ointment/past or patch and was exposed area thoroughly with soap and water. GI decontamination is not effective after sublingual exposure and is unlikely to be useful for regular release formulations because of rapid absorption and short half-life.
  • D) AIRWAY MANAGEMENT
    • 1) Perform early in patients with severe intoxication (eg, respiratory depression, severe hypotension).
  • E) ANTIDOTE
    • 1) There is no antidote for nitroglycerin. Methylene blue is the antidote for methemoglobinemia.
  • F) HYPOTENSION
    • 1) Obtain intravenous access. Initiate treatment with intravenous fluids. If hypotension persists, initiate pressors and titrate to a mean arterial pressure of at least 60 mmHg. Direct-acting pressors such as epinephrine and norepinephrine are preferred. Insert foley catheter and monitor urine output.
  • G) RESPIRATORY ARREST
    • 1) Respiratory depression is uncommon and can be treated with intubation and mechanical ventilation.
  • H) TACHYCARDIA
    • 1) Tachycardia is usually reflex tachycardia in the setting of hypotension and improves with administration of intravenous fluids.
  • I) 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.
  • J) ENHANCED ELIMINATION PROCEDURE
    • 1) Hemodialysis or hemoperfusion are not effective because of the large volume of distribution.
  • K) PATIENT DISPOSITION
    • 1) HOME CRITERIA: Asymptomatic patients with inadvertent overdose may be monitored at home, however, patients may require evaluation for chest pain, if that is the reason for the inadvertent overdose.
    • 2) OBSERVATION CRITERIA: Patients with deliberate ingestions and symptomatic patients should be sent to a health care facility for observation for at least 4 hours. With extended-release ISOSORBIDE MONONITRATE ingestion, patients should be observed for 6 to 10 hours as onset of effects may be delayed (Tmax for therapeutic doses is 3 to 4.5 hours)
    • 3) ADMISSION CRITERIA: Patients with persistent hypotension or methemoglobinemia should be admitted to hospital. Patients with significant persistent hypotension or methemoglobinemia should be admitted to an intensive care unit.
    • 4) CONSULT CRITERIA: Consult a poison center or medical toxicologist for assistance in managing patients with severe toxicity (severe hypotension, or severe methemoglobinemia), or in whom the diagnosis is not clear.
  • L) PITFALLS
    • 1) Failure to recognize nitroglycerin toxicity and/or methemoglobinemia. Ingestions are unlikely to result in severe toxicity, because of extensive first pass metabolism and short duration of action of most products; do not overtreat.
  • M) PHARMACOKINETICS
    • 1) Nitroglycerin is well absorbed via dermal and sublingual routes. Oral bioavailability is poor as first pass effect is very high. A subcutaneous depo may remain and cause effects for days after removal of patch. Absorption is rapid, there is extensive hepatic metabolism and half-life is short (2 to 3 minutes for nitroglycerin, up to 60 minutes for isosorbide dinitrate). Volume of distribution is 2 to 4 L/kg. Tmax for immediate release tablets is an hour or less, for extended release formulation it is 3 to 4.5 hours.
  • N) DRUG INTERACTIONS
    • 1) Use of selective phosphodiesterase inhibitors, such as sildenafil, tadalafil and vardenafil, can intensify the effect of nitroglycerin causing severe hypotension. Several "all natural" proprietary male enhancement supplements have been found to contain sildenafil and thus, may potentiate the effects of nitroglycerin.
  • O) DIFFERENTIAL DIAGNOSIS
    • 1) Any entity that can cause hypotension with tachycardia, including sepsis, cyanide poisoning, other vasodilatory agents, and clonidine.
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.
0.4.5 DERMAL EXPOSURE
  • A) OVERVIEW
    • 1) Nitroglycerin is well absorbed through the skin.
    • 2) Remove nitroglycerin ointment or transdermal patch (if applicable), and wash the skin thoroughly with soap and water.
Find more information on this substance at: Hazardous Substances Data Bank , TOXNET , PubMed