View source for Methylene blue

==Administration==
*Type: [[Antidote]], [[Vasopressors]]
*Routes of Administration: IV

==Adult Dosing==
*Acquired methemoglobinemia: 1 mg/kg IV over 5-30min, may repeat in 1h with up to 1 mg/kg IV if methemoglobin level still >30% or symptoms persist
*Drug-induced methemoglobinemia: 1-2 mg/kg IV slowly over several minutes
*See [[vasopressors]]
**For hypotension refractory to catecholamine pressors
**Consider after catecholamine, [[vasopressin]], and mineralocorticoid refractive shock

==Pediatric Dosing==
*Same as weight-based adult dosing

==Special Populations==
*[[Drug Ratings in Pregnancy|Pregnancy Rating]]: X, Fetal risk has been demonstrated
*[[Lactation risk categories|Lactation risk]]: Infant risk cannot be ruled out
*Renal dosing: no adjustment
*Hepatic dosing: no adjustment

==Contraindications==
*Allergy to class/drug
*G6PD deficiency
*[[ARDS]]
*[[Pulmonary hypertension]]

==Adverse Reactions==
===Serious<ref>Pasin L et al. Methylene blue as a vasopressor: a meta-analysis of randomised trials. Crit Care Resusc. 2013 Mar;15(1):42-8.</ref>===
*Hemolytic anemia
*Syncope
*Serotonin syndrome
*Paradoxical [[methemoglobinemia]] at doses > 4 mg/kg/hr or per bolus
*Pulmonary vasoconstriction at 3-4 mg/kg/hr or per bolus

===Common===
*Skin discoloration, urine discoloration, hyperhidrosis
*Nausea, abnormal taste
*Limb pain
*Dizziness, headache

==Pharmacology==
*Half-life: 24h
*Metabolism: Hepatic
*Excretion: Mostly renal

==Mechanism of Action==
*Promotes non-enzymatic redox conversion of methemoglobin to hemoglobin
*Improves vascular tone via inhibition of nitric oxide synthase

==Comments==

==Indications by Condition==
''The following table is automatically generated from disease/condition pages across WikEM.''

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==See Also==
*[[Methemoglobinemia]]
*[[Antidotes]]
==References==
<references/>
[[Category:Pharmacology]]
[[Category:Toxicology]]