From the Guidelines
Methylene Blue (methylthioninium chloride) supplementation is primarily used to treat methemoglobinemia, and its effects include reducing methemoglobin levels by accepting an electron from NADPH and converting back to the ferrous state in erythrocytes.
Effects of Methylene Blue Supplementation
- The usual starting dose is 1-2 mg/kg (0.2 mL/kg of a 1% solution) infused intravenously over 3 to 5 minutes, with a maximum dose of 5-7 mg/kg 1.
- Methylene blue should reduce methemoglobin levels significantly in less than an hour, with the dose repeated at 1 mg/kg if methemoglobinemia does not significantly decrease within 30-60 minutes 1.
- In cases of worsening methemoglobinemia after methylene blue treatment, urgent exchange transfusion should be performed 1.
Important Considerations
- Methylene blue should be used with caution in patients with G6PD deficiency, as it may induce hemolysis and worsen methemoglobinemia 1.
- Methylene blue may precipitate serotonin syndrome in individuals receiving selective serotonin reuptake inhibitors and other serotonergic antidepressants 1.
- Methylene blue should be used with caution in pregnant women due to concerns about teratogenicity and possible intestinal atresia 1.
- Methylene blue should be used cautiously in patients with renal failure and in anesthetized patients where it may inhibit guanylate cyclase, decreasing nitric oxide-mediated vasodilatation leading to systemic and pulmonary hypertension 1.
Treatment Guidelines
- The first-line treatment of methemoglobinemia is intravenous methylene blue, which acts as a cofactor to reduce methemoglobin to oxyhemoglobin in erythrocytes 1.
- Ascorbic acid can be given orally, intramuscularly, or intravenously, and many reports suggest the addition of ascorbic acid to methylene blue 1.
- If there is no improvement with the use of repeated doses of methylene blue, therapeutic whole blood exchange or hyperbaric oxygen therapy should be considered 1.
From the Research
Effects of Methylene Blue Supplementation
The effects of Methylene Blue (methylthioninium chloride) supplementation have been studied in various contexts, including its potential therapeutic benefits and adverse effects. Some of the key findings include:
- Antidepressant, anxiolytic, and neuroprotective properties, as documented by both animal and human studies 2
- Improvement in cognitive impairment during chronic cerebral hypoperfusion, with potential benefits for conditions such as mild cognitive impairment, vascular dementia, and Alzheimer's disease 3
- Upregulation of Nrf2/ARE genes and prevention of tau-related neurotoxicity, suggesting potential benefits for the treatment of neurodegenerative diseases with tau pathology 4
- Adverse effects on peripheral neurons, including neurotoxicity and altered membrane electrical properties, at certain concentrations 5
- Neuroprotective effects, including reduction of infarct volume and behavioral deficits, inhibition of apoptosis, and enhancement of autophagy, in models of ischemic stroke 6
Therapeutic Benefits
The therapeutic benefits of Methylene Blue supplementation have been explored in various studies, including:
- Treatment of neuropsychiatric disorders, such as bipolar disorder, with promising results in both short- and long-term treatment 2
- Improvement in cognitive function and memory consolidation, particularly in conditions involving chronic cerebral hypoperfusion 3
- Potential benefits for the treatment of neurodegenerative diseases with tau pathology, such as Alzheimer's disease and tauopathies 4
Adverse Effects
The adverse effects of Methylene Blue supplementation have also been studied, including: