Blue cures blue but be cautious

Abstract

Methemoglobinemia is a disorder characterized by the presence of >1% methemoglobin (metHb) in the blood. Spontaneous formation of methemoglobin is normally counteracted by protective enzyme systems, for example, nicotinamide adenine dinucleotide phosphate (NADPH) methemoglobin reductase. Methemoglobinemia is treated with supplemental oxygen and methylene blue (1–2 mg/kg) administered slow intravenously, which acts by providing an artificial electron acceptor for NADPH methemoglobin reductase. But known or suspected glucose-6-phosphate dehydrogenase (G6PD) deficiency is a relative contraindication to the use of methylene blue because G6PD is the key enzyme in the formation of NADPH through pentose phosphate pathway and G6PD-deficient individuals generate insufficient NADPH to efficiently reduce methylene blue to leukomethylene blue, which is necessary for the activation of the NADPH-dependent methemoglobin reductase system. So, we should be careful using methylene blue in methemoglobinemia patient before G6PD levels.

P-Chloroaniline Poisoning Causing Methemoglobinemia: A Case Report and Review of the Literature

“…Methylene blue should be used with caution in individuals with severe renal insufficiency and in young patients with G6PD deficiency. This group of patients can develop hemolytic anemia characterized by formation of Heinz bodies without any reduction in MetHb levels [ 14 , 20 , 23 ]. Alternative therapies include exchange transfusion, hyperbaric oxygen, and ascorbic acid [ 24 ].…”

Computational Study of Glucose-6-phosphate-dehydrogenase deficiencies using Molecular Dynamics Simulation

“…G6PD enzyme protects the blood cells against oxidative damage by maintaining the level of the NADPH. The NADPH in turn maintains the supply of reduced glutathione in the cells that is used to neutralize reactive oxygen species (Sikka et al, 2011). Previous study on G6PD variants found six German Ancestral G6PD variants (Roman and Swindells, 2011) of which, three particular variants (Vancouver, Aachen and Wayne) were found to locate within the active site region (Figure 1).…”

Friend or enemy? Review of 17β‐HSD10 and its role in human health or disease

“…Another compound which is potentially connected with 17β‐HSD10 modulation is methylene blue (MB, methylthionium chloride, 19, Figure 9) (Zakaria, Hamdi, & Abdel‐Kader, 2016). MB is an FDA approved drug for methemoglobinemia therapy (Sikka, Kapoor, Saxena, Bindra, & Jain, 2011), but recently came into interest as a possible therapy for Alzheimer´s disease. Methylene blue is reported to enhance cell viability, reduce Aβ oligomerization, and both 17β‐HSD10 function and protein expression level in LPS (lipopolysaccharide) mouse model (Zakaria et al., 2016).…”