The EMA European Public Assessment Report (EPAR) for methylthioninium chloride Proveblue (also known as methylene blue) contains information regarding contraindication of the drug in patients with G6PD deficiency due to risk of hemolytic anemia, and in patients with a deficiency in NADPH reductase (encoded by the BLVRB gene). The label also states that failure to respond to the drug may indicate a deficiency in cytochrome b5 reductase (CYB5R3) or G6PD.
Excerpts from the methylthioninium chloride Proveblue (methylene blue) EPAR:
- Hypersensitivity to the active substance, or to any other thiazine dyes
- Patients with Glucose-6-phosphate dehydrogenase deficiency (G6PD) due to the risk of
- Patients with sodium nitrite-induced methaemoglobinaemia
- Patients with methaemoglobinaemia due to chlorate poisoning
- Deficiency in NADPH reductase.
Failure to respond to methylthioninium chloride suggests cytochrome b5 reductase deficiency, glucose-6- phosphate dehydrogenase deficiency or sulfhaemoglobinemia. Alternative treatment options should be considered.
This information is highlighted in the following sections:
Contraindications, special warnings and precautions for use, package leaflet: information for the user.
For the complete drug label text with sections containing pharmacogenetic information highlighted, see the methylthioninium chloride Proveblue (methylene blue) EMA drug label.
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