Methylene Blue Toxicity - Causes, Symptoms, and Management

Introduction:

Dyes are organic compounds with a distinctive color that absorb light and give color to the visible region. The first synthetic dye, Mauveine (an organic aniline dye), was discovered in 1856 by William Henry Perkin. Dyes are applied to substrates to give them a permanent color that can withstand exposure to water, light, oxidizing agents, sweat, and microbial attack. This has led to the use of various dyes in different industries such as textiles, food, rubber, printing, cosmetics, medicine, plastic, concrete, and paper. Textile dyes, which are complex compounds with different structural groups, are used extensively in the textile industry. One of the most commonly used dyes in the industry is methylene blue (MB), which is used to color silk, wool, cotton, and paper.

What Is Methylene Blue?

Methylene blue is an artificial substance that was initially found in the 19th century and has since been used for various applications in both the medical and industrial fields. Methylene blue has many uses in medicine as an inhibitor of nitric oxide synthase and guanylate cyclase. Nitric oxide synthase and guanylate cyclase are enzymes that play important roles in regulating various physiological processes in the body, including the relaxation of blood vessels, neurotransmission, and immune function.

Methylene blue can help alleviate hypotension in several clinical conditions and improve hypoxia (a condition in which the body or a part of the body is deprived of adequate oxygen supply) and hyperdynamic circulation (a state in which the heart is pumping an abnormally large volume of blood, often resulting in an increased heart rate and decreased blood pressure) in cases of severe liver diseases. Additionally, it has been shown to produce a temporary but consistent improvement in blood pressure and cardiac function in patients with septic shock. Septic shock is a severe medical condition that can occur when an infection triggers an inflammatory response, leading to low blood pressure and multiple organ failure.

What Are the Uses of Methylene Blue?

There are many uses for methylene blue. Some uses include the following.

• Methemoglobinemia Treatment: Methylene blue is used to treat methemoglobinemia, a condition in which the blood is unable to carry oxygen properly, by reducing the levels of methemoglobin in the blood.

• Diagnostic Aid: Methylene blue is used as a diagnostic aid to help identify certain medical conditions, such as urinary tract infections or malabsorption syndromes. It stains cells and tissues.

• Cyanide Poisoning: Methylene blue can be used as an antidote for cyanide poisoning in some cases.

• Treating Vasoplegic Syndrome: Methylene blue has been used to treat vasoplegic syndrome, a condition in which blood vessels dilate excessively and blood pressure drops dangerously low during surgery.

• Treatment of Neurodegenerative Disorders: Methylene blue has shown promise in the treatment of certain neurodegenerative disorders, such as Alzheimer's disease and Parkinson's disease, by reducing the buildup of toxic proteins in the brain.

• Photodynamic Therapy: Methylene blue is used as an agent in this therapy for the treatment of certain types of cancer.

• Fish Disease Treatment: In the aquarium industry, methylene blue has been used to treat fish diseases such as fungal infections due to its antiparasitic and antifungal properties. It functions as an antiseptic in an aquarium.

What Is Methylene Blue Toxicity?

Methylene blue toxicity refers to the harmful effects that can occur when methylene blue, a medication used for treating methemoglobinemia and other conditions, or by individuals who are sensitive to the medication. It is generally considered safe when used as directed but can cause a range of adverse effects when taken in excessive amounts or when it is used inappropriately or by individuals who are sensitive to the medication.

The use of methylene blue is considered safe at a therapeutic dose of less than 2 mg/kg (milligram per kilogram). However, if levels exceed 7 mg/kg, numerous adverse effects may arise. Combining methylene blue with serotonergic agents at a dose of 5 mg/kg has been found to cause serotonin syndrome. Additionally, methylene blue should be used with caution in patients with renal failure since it can decrease renal blood flow. Patients taking any medication with serotonergic activity, such as SSRIs, should avoid the use of methylene blue due to the potential for serotonin syndrome, as noted in the adverse effects.

What Are the Causes Of Methylene Blue Toxicity?

Methylene blue toxicity develops due to various reasons which include:

• Overdose: Taking too much methylene blue at once or taking it more frequently than prescribed can lead to toxicity.

• Drug Interactions: Methylene blue can interact with other medications, such as Dapsone, Monoamine oxidase inhibitors (MAOIs), and selective serotonin reuptake inhibitors (SSRIs) increasing the risk of toxicity.

• Administration Method: Methylene blue can be given through oral or intravenous route. Giving methylene blue intravenously or too quickly can increase the risk of toxicity.

• Pre-existing Medical Conditions: People with kidney or liver disease may be at a higher risk of toxicity due to their reduced ability to clear the medication from their system.

• Allergic Reaction: Some individuals may be allergic to methylene blue, which can lead to a severe reaction and increase the risk of toxicity.

What Are the Symptoms of Methylene Blue Toxicity?

The symptoms of methylene blue toxicity can vary depending on the dose and method of administration, as well as the age and health of the patient. Some of the common symptoms of methylene blue toxicity include:

• Blurred vision.

• Headache.

• Nausea and vomiting.

• Diarrhea.

• Increased heart rate.

• Respiratory distress.

• Kidney damage.

What Is the Treatment for Methylene Blue Toxicity?

In most cases, treatment for methylene blue toxicity will involve supportive care to manage the symptoms and prevent further complications. This may include:

• Fluids and Electrolytes: Intravenous fluids and electrolytes may be given to help support kidney function and prevent dehydration.

• Oxygen Therapy: If respiratory distress is present, supplemental oxygen may be given to support breathing and increase oxygen levels in the blood.

• Dialysis: If kidney damage has occurred, dialysis may be necessary to remove excess methylene blue from the blood and support kidney function.

• Supportive Measures: Depending on the severity of the symptoms, additional supportive measures may be necessary, such as cardiac monitoring, respiratory support, or transfusion of blood products.

Conclusion:

Methylene blue is a valuable medication used for different purposes. However, it can be toxic if misused or in excess. Healthcare professionals must exercise caution when administering methylene blue and carefully monitor patients for signs of toxicity. By doing so, ensure that this medication continues to be a safe and effective treatment option for individuals who need it.