Key points

  • We recommend to consult your poison centre with the use of this antidote.
  • Methylene blue may be less effective or ineffective in patients deficient in glucose - 6 - phosphate dehydrogenase (G6PD); it may even cause hemolysis. However, it is not contraindicated in the event of partial deficiency.
  • If ineffective, consider hyperbaric oxygen therapy (children, adults) or whole blood exchange transfusion (newborns, infants)
  • When correction of methemoglobinemia is slow, consider the possibility of a G6PD deficiency or the ongoing absorption of the toxic agent.
  • In case of methemoglobinemia without access to IV methylene blue, consult your poison center. More invasive therapies such as exchange transfusion may be considered on a case by case basis.
  • WARNING:Health Canada notice issued on February 16, 2011:  Methylene blue injectable in combination with serotonin reuptake inhibitors - Association with serotonin toxicity

© Centre antipoison du Québec, CIUSSS de la Capitale-Nationale, 2017. The information contained in this site may be cited, provided the source is acknowledged. Any use for commercial or advertising purposes is strictly prohibited.

Last updated : 2022-12-13