Methylene Blue Quiz

In a therapeutic setting, methylene blue reduces the Fe3+ to Fe2+, and thereby alleviates the dysfunction of methemoglobinemia. Ferrous is the Fe2+ state which is able to adequately bind oxygen. Ferric is the Fe3+ state which is unable to adequately bind oxygen for transport to the tissues.

Out of all of the answer choices, the only relative contraindication for administration of methylene blue is concomitant use of an SSRI. The reasons for this is that there is possibility of development of serotonin syndrome. The mechanisms underlying this interaction are unclear, but have been reported. However, on theory is that methylene blue may inhibit monoamine oxidase (MAO). All of the other answer choices are incorrect.

In a patient that has received methylene blue, the foley output tends to be purple in color until the methylene blue is cleared. Although, google search of this will portray multiple color outcomes, purple is the authors personal experience.

Methylene blue requires NADPH within the cytosol of the RBC to reduce the Fe3+heme to Fe2+heme. NADPH reduce Methylene blue to leukomthylene blue, which then reduces Ferric-Heme to Ferrous-Heme, effectively reversing Methemogloblinemia.

Administration of Methylene blue has been associated with hemolysis. NMS is no associated with Methylene blue administration. However, seratonin syndrome has been triggered by its administration, especially in the setting of a concomitant MAOi. Methylene blue administration may reverse hypotension in the setting of vasopressor refractory shock, however data are limited. Transient paralysis is not associated with Methylene blue administration. Tardive dyskinesia is associated with long term administration of neuroleptic medications.

Methylene blue should exert its max pharmacodynamic effect for the treatment of methemoglobinemia within 30 minutes. If repeat cooximetry demonstrates refractory methemoglobinemia, repeat dosing may be indicated.

The dose can be repeated within 30-60 minutes if the response to the treatment is no adequate. Keep in mind that methylene blue can cause substantial pain at at the site of infusion, even if you have nice access with an 18g in the AC.