methylene blue

Action and Spectrum

Actions and Spectrum:

The mechanism of action of methylene blue involves its ability to reduce the oxidized form of the enzyme cytochrome c oxidase, which is involved in the production of cellular energy in the form of ATP. By reducing this enzyme, methylene blue can increase the production of ATP, leading to improved cellular function.

In addition to its effects on cytochrome c oxidase, methylene blue has antioxidant properties and can scavenge free radicals and reduce oxidative stress.

The spectrum of activity of methylene blue is relatively broad. It is effective against various bacteria, including Staphylococcus aureus, Streptococcus pneumoniae, and Pseudomonas aeruginosa. It has also been shown to have antifungal activity against Candida albicans and Aspergillus fumigatus. In addition, methylene blue has antiviral properties and has been shown to inhibit the replication of several viruses, including HIV-1, hepatitis B, and influenza A.

Drug Interaction

Adverse Reaction

Frequency defined

>10%

Chromaturia (74%)

Feeling hot (17%)

Hyperhidrosis (13%)

Skin discoloration (13%)

Pain in extremities (84%)

Dysgeusia (20%)

Dizziness (16%)

Nausea (13%)

1-10%

Musculoskeletal pain (9%)

Paresthesia (9%)

Feeling cold (6%)

Contact dermatitis (5%)

Pruritus (4%)

Decreased appetite (4%)

Back pain (2%)

Headache (10%)

Paresthesia oral (9%)

Infusion site pain (6%)

Pallor (5%)

Syncope (4%)

Anxiety (4%)

Chest discomfort (4%)

Black Box Warning

Black box warning:

Administered with serotonergic medications, it may result in severe or deadly serotonergic syndrome.

SSRIs, SNRIs, and MAOIs should not be administered together.

Contraindication / Caution

Contraindications/caution:

Contraindications:

• Hypersensitivity or allergy to methylene blue: Individuals with an allergic reaction or hypersensitivity to methylene blue or its components should not use the medication.
• Glucose-6-phosphate dehydrogenase (G6PD) deficiency: methylene blue can cause hemolytic anemia in individuals with G6PD deficiency, a genetic condition that affects red blood cells.
• Renal failure: methylene blue can accumulate in the body and cause toxicity in individuals with severe kidney impairment or failure.
• Serotonin syndrome: methylene blue can increase serotonin levels in the body and may cause serotonin syndrome in individuals taking other medications that increase serotonin levels.
• Methemoglobinemia: methylene blue should not be used to treat methemoglobinemia caused by nitrate medications, as it can worsen the condition.
• Pregnancy and breastfeeding: methylene blue should be used cautiously during pregnancy and breastfeeding, as its effects on the fetus or infant are not well-established.

Caution:

• Interaction with other medications: methylene blue can interact with other medications, including antidepressants, antipsychotics, and certain antibiotics, and may increase their side effects.
• Use in elderly patients: Elderly patients may be more sensitive to the effects of methylene blue and may require a lower dose.
• Use in pediatric patients: methylene blue may be used in pediatric patients, but the dose should be adjusted based on the child’s weight and age, and the medication should be used cautiously.
• Use in patients with liver disease: methylene blue can accumulate in the body and cause toxicity in patients with liver disease.
• Use in patients with glucose-6-phosphate dehydrogenase (G6PD) deficiency: While methylene blue is contraindicated in patients with G6PD deficiency, if its use is necessary, patients should be monitored closely for signs of hemolysis.

Side effects: methylene blue can cause side effects, including nausea, vomiting, headache, dizziness, confusion, and high blood pressure.

Pregnancy / Lactation

Pregnancy consideration: When given to a pregnant woman, it can cause fetal damage.

Intra-amniotic injection of a methylene blue class product into pregnant women during the second trimester was linked to newborn intestinal atresia and fetal mortality.

Lactation: Excretion of the drug in human breast milk is unknown

Pregnancy category:

Category A: well-controlled and Satisfactory studies show no risk to the fetus in the first or later trimester.

Category B: there was no evidence of risk to the fetus in animal studies, and there were not enough studies on pregnant women.

Category C: there was evidence of risk of adverse effects in animal reproduction studies, and no adequate evidence in human studies must take care of potential risks in pregnant women.

Category D: adequate data with sufficient evidence of human fetal risk from various platforms, but despite the potential risk, and used only in emergency cases for potential benefits.

Category X: Drugs listed in this category outweigh the risks over benefits. Hence these categories of drugs need to be avoided by pregnant women.

Category N: There is no data available for the drug under this category

Pharmacology

Pharmacology:

• methylene blue is a medication with various pharmacological properties, including dye, anti-infective, antioxidant, and vasopressor effects.
• methylene blue works by inhibiting nitric oxide synthase, an enzyme responsible for producing nitric oxide, a potent vasodilator. methylene blue can increase blood pressure and improve blood flow in certain medical conditions by inhibiting nitric oxide production.
• methylene blue can also reduce methemoglobin levels by increasing the ability of red blood cells to carry oxygen. In addition, it has been shown to have antimicrobial properties and can inhibit the growth of certain bacteria and parasites.

Pharmacodynamics:

The pharmacodynamics of methylene blue involve its interaction with various cellular targets and biological processes in the body.

methylene blue works primarily as an inhibitor of nitric oxide synthase (NOS), an enzyme that produces nitric oxide (NO) from L-arginine. By inhibiting NOS, methylene blue reduces the production of NO, a potent vasodilator, thereby increasing blood pressure. methylene blue also inhibits guanylate cyclase, which converts guanosine triphosphate (GTP) to cyclic guanosine monophosphate (cGMP), a signaling molecule involved in vasodilation. By inhibiting guanylate cyclase, methylene blue further enhances its vasoconstrictive effects.

Pharmacokinetics:

Absorption

methylene blue can be administered orally or intravenously. When given orally, it is rapidly absorbed from the gastrointestinal tract and enters the bloodstream. When given intravenously, it is immediately available in systemic circulation.

Distribution

methylene blue has a relatively large volume of distribution, meaning it distributes widely throughout the body. It can cross the blood-brain barrier and placenta and is distributed into breast milk.

Metabolism

methylene blue undergoes extensive first-pass metabolism in the liver, where it is primarily metabolized by monoamine oxidase (MAO) to form leucomethylene blue. Leucomethylene blue is then metabolized by glucuronyl transferase and excreted in the urine.

Elimination and Excretion

methylene blue and its metabolites are primarily excreted in the urine, with a small portion eliminated in the feces. The elimination half-life of methylene blue is approximately 4-6 hours.

Adminstartion

Administration:

Depending on the treated condition, methylene blue can be administered orally or intravenously. The dosage and route of administration will vary depending on the patient’s age, weight, medical condition, and other factors.

For methemoglobinemia, a condition in which the blood cannot carry oxygen effectively, methylene blue is usually given intravenously at a dose of 1-2 mg/kg of body weight over 5-10 minutes. The dose may be repeated if necessary.

For malaria, methylene blue is typically given orally at 10-15 mg/kg of body weight once daily for 3-5 days. It may be given in combination with other antimalarial medications.

For urinary tract infections, methylene blue is sometimes given orally at a dose of 100-200 mg three times daily for up to two weeks.

Patient Information Leaflet

Patient information leaflet

Generic Name: methylene blue

Why do we use methylene blue?

methylene blue has several medical uses, including:

• Methemoglobinemia: methylene blue treats methemoglobinemia, a condition in which the blood cannot carry oxygen effectively. Methylene blue acts as a reducing agent and converts methemoglobin to hemoglobin, which can carry oxygen more efficiently.
• Malaria: methylene blue is used as an alternative treatment for malaria, particularly in areas where resistance to other antimalarial drugs is common. Methylene blue is thought to work by interfering with the metabolic processes of the malaria parasite.
• Urinary tract infections: methylene blue is sometimes used as an adjunctive treatment for urinary tract infections. It may work by preventing the bacteria that cause the infection from adhering to the urinary tract walls.
• Diagnostic tool: methylene blue is also used as a diagnostic tool in various medical procedures. For example, it can be used to identify the location of a ureter during surgery, as it can stain urine and make it easier to identify the ureter.

Photodynamic therapy: methylene blue has also been investigated for its potential use in photodynamic therapy, a type of cancer treatment that uses light-sensitive drugs and a particular light source to destroy cancer cells.