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Methylene Blue

Presentation

1% 50mg in 5mls

Role

  • Management of symptomatic methaemoglobinaemia with chest pain, dyspnoea, confusion and methaemoglobin concentrations > 20%.
  • Management of methaemoglobin concentration >30% (lower treatment thresholds are indicated in severe anaemia).
  • Vasoplegic shock resistant to high dose vasopressor therapy (noradrenaline, vasopressin).
Methylene Blue
  • ALERT – Consultation with a clinical toxicologist is recommended through the local toxicology service or Poisons Information Centre 13 11 26.

Dose

Management of symptomatic methaemoglobinaemia

  • 1mg/kg IV as bolus over 5 minutes, can repeat once at 30 minutes

Management of vasoplegic shock not responding to high dose standard vasopressor therapy

  • 2mg/kg IV as bolus over 5 minutes

Stocking recommendations

Tertiary centre Regional centre Rural centre Remote centre

6 vials

6 vials 0 – 6 vials 0 vials

Rationale

Methylene Blue is often available in hospitals for other indications – including as a surgical dye. Six vials are sufficient to manage the scenarios listed above.

Precautions

  • Methylene blue in doses >7mg/kg given over a short period (2-3 hours) may cause paradoxical methaemoglobinaemia.
  • Methylene blue is a monoamine oxide inhibitor (MAOI). In the presence of other serotonergic agents, it may precipitate serotonin toxicity.
  • Methylene blue is teratogenic.

Disclaimer

Fact sheet developed by Queensland Poisons Information Centre, Updated: July 2020.

This fact sheet is about the use of these antidotes in Australia, and may not apply to other countries. Children’s Health Queensland Hospital and Health Service cannot be held responsible for the accuracy of information, omissions of information, or any actions that may be taken as a consequence of reading this fact sheet.

CHQ