Methylene blue
Dosing in kidney impairment
Recommended Dosage for Renal Impairment The recommended dosage of methylene blue injection in patients with moderate or severe renal impairment (eGFR 15-59 mL/min/1.73 m 2 ) is a single dose of 1 mg/kg. If the methemoglobin level remains greater than 30% or if the clinical symptoms persist 1 hour after dosing, consider initiating alternative interventions for the treatment of methemoglobinemia.
Dosing in liver impairment
Hepatic Impairment Methylene blue is extensively metabolized in the liver. Monitor patients with any hepatic impairment for toxicities and potential drug interactions for an extended period of time following treatment with methylene blue.
Preparation and administration
Dosage and Administration Ensure patent venous access prior to administration of methylene blue injection. Do not administer methylene blue injection subcutaneously. Administer methylene blue injection 1 mg/kg intravenously over 5-30 minutes. If the methemoglobin level remains greater than 30% or if clinical signs and symptoms persist, a repeat dose of methylene blue injection 1 mg/kg may be given one hour after the first dose.
If methemoglobinemia does not resolve after 2 doses of methylene blue injection, consider initiating alternative interventions for treatment of methemoglobinemia.
Preparation Methylene blue injection is hypotonic and may be diluted before use in a solution of 50 mL 5% Dextrose Injection in order to avoid local pain, particularly in the pediatric population. Use the diluted solution immediately after preparation. Avoid diluting with sodium chloride solutions, because it has been demonstrated that chloride reduces the solubility of methylene blue.
Parenteral drug products should be inspected visually for particulate matter and discoloration prior to administration, whenever solution and container permit. Discard unused portion.