Methylene Blue

Methylene blue is a phenothiazine derivative used for a variety of medical purposes such as, as a diagnostic agent, an antidote against beta-blocker or calcium channel blocker overdose, treatment of methemoglobinemia, and more. Since its mechanism of action depends on its use and concentration, products are available in multiple formulations. Here at CareFirst Specialty Pharmacy, we can compound Methylene blue into an array of different strength capsules.

Pronunciation:

(METH i leen bloo)

Other Names:

Brand Names (U.S.): ProvayBlue

Drug Class:

Phenothiazine Derivative, Antidote, Anti-Infective Agent, Antiseptic, Diagnostic Agent

Mechanism of Action:

In methemoglobinemia treatment, low concentrations of methylene blue facilitate the conversion of methemoglobin to hemoglobin. In cyanide toxicity, methemoglobin combines with cyanide to form cyanomethemoglobin preventing the interference of cyanide with the cytochrome system. In vasoplegia syndrome treatment, methylene blue may restore vascular tone by a direct inhibitory effect on endothelial nitric oxide synthase (eNOS) and inducible NOS (iNOS) by oxidation of enzyme-bound ferrous iron. Methylene blue also blocks the formation of cyclic guanosine monophosphate (cGMP) by inhibiting the guanylate cyclase enzyme through binding to iron in the heme complex thus reducing vasorelaxation.

Warning: High concentrations of methylene blue may convert the ferrous iron of reduced hemoglobin to ferric iron resulting in the formation of methemoglobin.

Adverse Effects:

Common side effects you might experience: dizziness, headache, diarrhea, abdominal pain, muscle pain, painful extremities, injection site pain, sensation of warmth or cold, change in taste, skin discoloration, and urine or stool discoloration.

Tell your doctor if you begin to have any of these symptoms following methylene blue administration:

• Signs of an allergic reaction like a rash, hives, itching, trouble breathing, wheezing, tightness in chest and/or throat.
• Signs of serotonin syndrome like dizziness, severe headache, agitation, sensing things that seem real but are not, fast heartbeat, arrhythmia, flushing, tremors, sweating a lot, change in balance, severe nausea, or severe diarrhea.
• Signs of hemolytic anemia like pale skin, jaundice (yellowish skin, eyes, and mouth), dark-colored urine, fever, weakness, dizziness, and confusion.

Administration

Use this drug as ordered by your prescriber.

Dosing:

Contact your healthcare provider for specific dosing instructions.

Pregnancy:

Methylene blue does cross the placenta. It is best to speak to your healthcare provider to see if benefits outweigh risks of using methylene blue while pregnant.

Breasefeeding:

It is not known if methylene blue is excreted in breast milk. One manufacturer recommends discontinuing breastfeeding during treatment and for up to 8 days after therapy is complete.

Children/Pediatrics:

For infants, children, and adolescents, methylene blue is relatively safe to use; however, dosing is subject to change based on age and weight.

References:

• Methylene Blue [Lexi-Drugs]. Lexi-Comp. Wolters Kluwer Health, Inc. https://online.lexi.com/. Updated July 26, 2023. Accessed July 31, 2023.
• Product Information: PROVAYBLUE(TM) intravenous injection, methylene blue intravenous injection. American Regent (per FDA), Shirley, NY, 2016.
• Grauman Neander N, Loner CA, Rotoli JM. The Acute Treatment of Methemoglobinemia in Pregnancy. J Emerg Med. 2018 May;54(5):685-689. doi: 10.1016/j.jemermed.2018.01.038.