Methylene blue, also known as methylthioninium chloride, is a medication and dye. As a medication it is mainly used to treat methemoglobinemia. Specifically it is used to treat methemoglobinemia levels that are greater than 30% or in which there are symptoms despite oxygen therapy. It has previously been used for cyanide poisoning and urinary tract infections but this use is no longer recommended.Wikipedia
The FDA and the EMA have issued precautions for the use of methylene blue in patients who are G6PD-deficient due to risk of hemolytic anemia, and in patients with a deficiency in NADPH reductase (encoded by the BLVRB gene).
|Genotype/Genoset||Diplotype||Gene||Drug Use/Category/Class||Medical Field||Summary||Descriptive Sentence|
|gs309||WT/WT||G6PD||Methemoglobinemia||Hematology||Normal Response Expected||You do not appear to carry any G6PD mutations linked to an unwanted side effect (hemolytic anemia).|
|gs307||Carrier||G6PD||Methemoglobinemia||Hematology||Use with Caution||You carry a G6PD mutation that might lead to an unwanted side effect (hemolytic anemia) when taking Methylene Blue; due to variable expression (i.e. in females), enzymatic testing for G6PD activity is advisable.|
|gs308||G6PD-deficient||G6PD||Methemoglobinemia||Hematology||Use with Caution||You carry a G6PD mutation linked to an unwanted side effect (hemolytic anemia) when taking methylene blue; use with caution.|