Product Monograph - Methylene Blue Injection
WARNING
Recent research has revealed that methylene blue has structural properties similar to Monoamine oxidase inhibitors (MAOI), known precipitants of serotonin toxicity when administered concomitantly with drugs having serotonin reuptake inhibition properties (SRls). Serotonin toxicity/serotonin syndrome has been reported when methylene blue was administered intravenously at concentrations as low as 1 mg/kg, in patients receiving Selective Serotonin Reuptake Inhibitors (SSRls) or other drugs with serotonin reuptake inhibition properties (e.g.: duloxetine, venlafaxine and clomipramine). Several of these cases required admission to Intensive Care Unit.
If SRls are being taken, careful consideration needs to be given to stop them before methylene blue injection use to allow a washout period equivalent to at least 4-5 half-lives.
ADVERSE EFFECTS
After I.V. administration Methylene Blue 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. Because Methylene Blue is a dye, preparations of the drug stain skin: stains on skin may be removed by use of a hypochlorite solution.
DOSAGE
For the treatment of drug-induced methemoglobinemia as in nitrite poisoning, Methylene Blue is administered I.V. 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 1 hour if required.
SUPPLIED
Each mL of sterile solution contains: tetramethylthionine chloride (methylene blue) trihydrate B.P. 10 mg in water for injection. Non-medicinal ingredients: sodium hydroxide and hydrochloric acid to adjust pH.
Vials of 5 mL, boxes of 10.
STORAGE
Store at room temperature (15°C to 30°C).
SINGLE USE VIAL
Discard unused portion.
Phebra Pty Ltd
19 Orion Road
Lane Cove West
Australia, 2066