methylene blue + nitric oxide

Methylene blue + nitric oxide is not a standard pharmaceutical combination but refers to the pharmacological interaction between methylene blue and the nitric oxide pathway. Methylene blue is a synthetic thiazine dye and small molecule drug primarily used as an antidote for methemoglobinemia. It acts by inhibiting both nitric oxide synthase and soluble guanylate cyclase, thereby reducing the production and downstream effects of nitric oxide, particularly in conditions like vasoplegic shock or septic shock[1][3][4][5][6]. Nitric oxide itself is a gaseous signaling molecule involved in vasodilation via activation of guanylate cyclase and increased cyclic GMP levels. Methylene blue’s inhibition of this pathway makes it useful in treating refractory hypotension due to excessive NO activity[3][4][5]. The two are mechanistically linked rather than co-administered as a fixed-dose combination.

Other names

tetramethylthionine chloride (for methylene blue)