Methylene Blue Injection USP Product Monograph

INDICATIONS AND CLINICAL USE:

Methylene Blue Injection USP is used in the treatment of methemoglobinemia. Methylene Blue Injection USP is also used as bacteriological stain, as a dye in diagnostic procedures such as fistula detection, and for the delineation of certain body tissues during surgery.

CONTRAINDICATIONS:

Methylene Blue Injection USP is contraindicated in patients with severe renal impairment or a known hypersensitivity to the drug.

PRECAUTIONS:

Methemoglobin concentration should be closely monitored during treatment as methylene blue can produce methemoglobinemia in large doses.

For management of a suspected drug overdose, contact your regional Poison Control Centre immediately.

Methylene Blue Injection USP should be used with caution in the treatment of toxic methemoglobinemia; high doses can cause hemolytic anemias and patients with glucose-6-phosphate dehydrogenase (G6PD) deficiencies are particularly susceptible.

A rapid disappearance of cyanosis in response to Methylene Blue Injection USP would be expected within one hour but might not occur if the patient has erythrocyte G6PD or NADPH-diaphorase deficiency or if methemoglobinemia is due to the ingestion of compounds such as aniline or dapsone. A second dose has been recommended if cyanosis does not disappear within one hour of Methylene Blue Injection USP administration but results of a study in animals and of patient with aniline poisoning indicated that an increased dosage of methylene blue might be of no additional benefit and could be potentially dangerous in that it could enhance Heinz body formation.

Methylene Blue Injection USP should not be injected subcutaneously as it may cause necrotic abscesses. It should not be given by intrathecal injection as neural damage has occurred. Methylene Blue Injection USP should be used with caution in patients with glucose-6-phosphate dehydrogenase deficiency.

PREGNANCY AND LACTATION:

Although intra-amniotic injection of methylene blue has been used to diagnose premature rupture of fetal membranes or to identify separate amniotic sacs in twin pregnancies, there have been several reports of hemolytic anemia (Heinz-body anemia) and hyperbilirubinemia in neonates exposed to methylene blue in the amniotic cavity. In most cases, exchanges transfusions, and/or phototherapy are required to control the jaundice.

ADVERSE REACTIONS:

After intravenous administration Methylene Blue Injection USP may cause nausea, vomiting, abdominal and chest pain, headache, dizziness, mental confusion, profuse sweating, and hypertension, with very high doses, methemoglobinemia and hemolysis may occur.

DOSAGE AND ADMINISTRATION:

As a methoglobinemic: For the treatment of drug induced methemoglobinemia as in nitrite poisoning. Methylene Blue Injection USP is administered intravenously as a 1% solution in doses of 1 to 2 mg/kg body weight injected over a period of several minutes. A repeat dose may be given after one hour if required.

As a diagnostic aid: For the detection of fistulas, 1 to 3 mL of Methylene Blue Injection USP is injected into the opening and the appearance of blue discoloration is observed in the surrounding tissue.

AVAILABILITY:

Each mL of sterile solution contains 10 mg of methylene blue (Tetramethylthionine chloride Trihydrate) in water for injection. Also contains sodium hydroxide and hydrochloric acid to adjust pH.

Ampoules of 5 mL, boxes of 5. Store at room temperature (15 to 30°C).

Questions or concerns?

Contact Hikma Canada Limited at 1-800-656-0793

Last Revised: April 14, 2022

REFERENCE:

Bioniche Pharma (Canada) Ltd, Prescribing Information, Methylene Blue Injection USP, DIN 02094665, February 22, 2011.