Methylene Blue
Class: Antidotes
VA Class: AD900
Molecular Formula: C16H18CIN3S.3H2O
CAS Number: 7220-79-3
Brands: ProvayBlue
Warning
- Serotonin Syndrome with Concomitant Use of Serotonergic Drugs
May cause serious or fatal serotonin syndrome when used concomitantly with serotonergic drugs.
Avoid concomitant use with drugs that enhance serotonergic transmission (e.g., SSRIs, SNRIs, MAO inhibitors). (See Serotonin Syndrome under Cautions.)
Introduction
Oxidation-reduction agent, thiazine dye; accelerates conversion of methemoglobin to hemoglobin.
Uses for Methylene Blue
Methemoglobinemia
Treatment of acquired methemoglobinemia. Designated orphan drug by FDA for this use.
Accelerated approval of methylene blue for this indication based on reduction (≥50%) in methemoglobin within 1 hour following IV administration of the drug in patients with methemoglobinemia; continued FDA approval for this indication may be contingent upon verification of clinical benefits in future clinical studies.
Used for methemoglobinemia associated with certain drugs (e.g., dapsone, benzocaine, lidocaine), occupational or other exposures to toxic chemicals (e.g., hydrazine, amine-substituted benzenes, nitro-substituted benzenes, nitrates, nitrites), or substance abuse (e.g., inhalation or ingestion of volatile nitrites). Methemoglobinemia may not resolve or may rebound after initial response to therapy with methylene blue in patients with methemoglobinemia associated with aryl amines (e.g., aniline) or sulfa drugs (e.g., dapsone).
Does not reverse methemoglobinemia in patients with glucose-6-phosphate dehydrogenase (G-6-PD) deficiency; may induce or exacerbate hemolysis in these patients. Methylene blue is contraindicated in patients with G-6-PD deficiency due to risk of hemolytic anemia. (See Contraindications and also see Hematologic Effects, under Cautions.)
Has been used for treatment of cyanosis in patients with congenital methemoglobinemia† related to cytochrome b5 reductase deficiency; ineffective in patients with hemoglobin M (abnormal hemoglobin molecules). Designated orphan drug by FDA for treatment of congenital methemoglobinemia.
Not effective for treatment of sulfhemoglobinemia.
Ifosfamide-induced Encephalopathy
Management of ifosfamide-induced encephalopathy†; may be beneficial in some patients, but additional study needed.
Has been ineffective when used prophylactically in an attempt to prevent ifosfamide-associated encephalopathy.
Use as a Dye
Has been used as a bacteriologic stain, as an indicator dye, and for surgical and medical marking.
Has been used as diagnostic (visualizing) dye† in a variety of procedures, including sentinel lymph node biopsy in cancer patients (e.g., breast cancer patients), endoscopic evaluation of lesions in patients with GERD or Barrett's esophagus, urologic evaluation in patients wi..
