Hydrazine toxicity

Background

  • Clear, colorless liquid that has an ammonia-like odor
  • Powerful reducing agent that is highly reactive
  • Exposure to metal oxides makes it highly exothermic and combustible
  • Used in rocket fuels, missile fuels, aircraft emergency power unit fuel (notably the F-16)
  • Used in chemical manufacturing (intermediate for insecticides/herbicides/dyes, polymerization catalyst for making plastics, used to manufacture sodium azide [air bag propellant], used to make isoniazid and fluconazole

Toxic Dose

  • OSHA limit 1 ppm in air for 8-hour workday
  • NIOSH recommends 0.03 ppm in air for 2-hour period
  • Odor threshold 3.7 ppm in air

Routes of Exposure

  • Inhalation
  • Skin contact / absorption (rapid within 30 seconds of contact)
  • Ingestion

Mechanism of Action

  • Hydrazine + ketone/aldehyde = hydrazones + B6 = hydrazones of pryidoxine
    • "consumes" B6 in body
    • functional B6 deficiency results
  • Metabolism of hydrazine produces free radical intermediates
  • Inhibits pyridoxine kinase as well as glutamic acid decarboxylase which results in decrease production of GABA neurotransmitter

Clinical Features

Differential Diagnosis

Evaluation

Management

Mild to Moderate Exposure

  • Ensure patient has been decontaminated
  • Irrigate eyes with normal saline or water if exposed
  • Treat chemical burns if present
  • Monitor pulmonary status
  • Monitor for development of methemoglobinemia

Severe Exposure

  • Seizures - pyridoxine 25 mg/kg IM or IV up to 5 grams plus benzodiazepine
  • Respiratory distress - secure airway and assist ventilation
  • Methemoglobinemia - initiate oxygen therapy, give methylene blue if patient is symptomatic; Methylene blue dose 1 mg/kg IV over 5 to 30 minutes repeat dose may be given 1 hour after first if symptoms persist
  • Consider hemodialysis and acidification of urine if member has severe CNS depression
  • Hypoglycemia treat with D10 and thiamine

Disposition

  • Home in cases of mild skin exposure without burns
  • Observation for patients with inhalation or ingestion exposure for at least 12 hours to ensure no serious symptoms develop
  • Admit patients with CNS symptoms or persistent pulmonary/gastrointestinal symptoms

See Also

References