To the Editor, The case report by Bauer et al is indeed interesting [1]. Rapid reversal of marked respiratory distress following methylene blue (MB) administration in a normotensive patient is of recent information. However, few aspects "of the report require contemplation. Epinephrine-resistant anaphylaxis is a strong stimulus to search for possible alternative therapies. The available evidences, although largely anecdotal, are compelling and supportive on the usefulness of MB to such patients who are in a state of severe anaphylaxis with vasodilatory shock and not responding to catecholamine therapy [2]. At the same time, we should recall the side effects, dosing, and patient safety while using MB and stress all these in health science education and training. Methylene blue has become an important therapeutic agent with diverse applications in clinical practice, but it is not a benign drug in view of side effects. Few serious side effects reported with MB are cardiac arrhythmias, coronary vasospasm, increased pulmonary hypertension, anaphylaxis [3], worsening of gas exchange, hemolytic anemia, hyperbilirubinemia, and altered regional outputs to the mesenteric or renal vasculature. In addition, MB is now recognized as a potent monoamine oxidase inhibitor. Hence, it has to be avoided in patients on serotonergic medications so as to prevent life-threatening serotonin toxicity. Another inconvenience with the use of MB is that the recipient has to be screened for G-6-P-D deficiency before administering MB. Interference by the dye may produce spurious results, or it complicates the laboratory procedure [4].
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