Product Overview:

Summary:

Methylene blue is an oxidation-reduction agent utilized primarily for treating acquired methemoglobinemia in both pediatric and adult patients. It has a rich history of medical use, including treatments for malaria and investigations into its potential for treating Alzheimer’s disease.

Brand Names:

• Hyophen
• Phosphasal
• Provayblue
• Proveblue
• Urelle
• Uribel
• Urimar (Reformulated Oct 2013)
• Urin DS
• Urogesic Blue (Reformulated Apr 2012)
• Ustell

Generic Name:

Methylene blue

Background:

Methylene blue serves as a versatile oxidation-reduction agent. The FDA approves its intravenous form for treating acquired methemoglobinemia in both children and adults. Historically significant in treating malaria in Africa, its use diminished with the advent of drugs like chloroquine. It’s also been researched as a urinary tract antiseptic and for its potential in Alzheimer’s disease due to its inhibition of Tau protein aggregation.

Type:

Small Molecule

Groups:

Approved, Investigational

Chemical Structure and Properties:

• Weight:
  • Average: 319.85
  • Monoisotopic: 319.0909965
• Chemical Formula:
  • C₁₆H₁₈ClN₃S
• Synonyms:
  • Azul de metileno
  • Basic Blue 9
  • Chlorure de méthylthioninium
  • Methylthioninium chloride

Pharmacology:

Indication:
Methylene blue is indicated for treating acquired methemoglobinemia in pediatric and adult patients. Other potential uses include managing hypotension, urinary tract infections, hypoxia in liver cirrhosis, hepatopulmonary syndrome, and ifosfamide-induced neurotoxicity.

Mechanism of Action:

• Methemoglobinemia: Converts oxidized hemoglobin back to its oxygen-carrying form.
• Alzheimer’s Disease: Inhibits Tau protein aggregation, reducing neuroinflammation.
• Malaria: Inhibits P. falciparum glutathione reductase and prevents hem polymerization.
• Ifosfamide Neurotoxicity: Acts as an alternate electron acceptor to reverse NADH inhibition and prevent toxic byproduct formation.

Pharmacokinetics:

• Volume of Distribution: 10 mg/kg (in rats)
• Protein Binding: 71-77% in rabbit plasma
• Metabolism: Rapid reduction to leukomethylene blue
• Elimination: Excreted in urine and bile, primarily as colorless leukomethylene blue
• Half-life: 5-6.5 hours (IV dose)
• Clearance: 3.0 ± 0.7 L/min

Toxicity:

LD50 = 1180 mg/kg (Rat)

Side Effects of Methylene Blue:

Methylene blue, like any medication, can have side effects. The severity and type of side effects can vary depending on the dosage and the individual patient’s response to the medication.

Common Side Effects:

• Gastrointestinal: Nausea, vomiting, diarrhea, abdominal pain.
• Neurological: Headache, dizziness, confusion, restlessness, tremor.
• Cardiovascular: Hypertension, chest pain, palpitations.
• Dermatological: Skin discoloration (blue or green tint), sweating.
• Urinary: Urine discoloration (green or blue tint).

Serious Side Effects:

• Serotonin Syndrome: Especially when used in combination with other serotonergic drugs, symptoms may include agitation, hallucinations, rapid heart rate, fever, muscle stiffness, loss of coordination.
• Methemoglobinemia: In rare cases, high doses can cause methemoglobinemia, the very condition it is used to treat, especially in patients with G6PD deficiency.
• Severe Allergic Reactions: Anaphylaxis, rash, itching, swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.
• Hemolytic Anemia: Particularly in patients with G6PD deficiency, leading to fatigue, paleness, shortness of breath, or yellowing of the skin and eyes.
• Respiratory Distress: Shortness of breath, rapid breathing, cyanosis (bluish discoloration of the skin).

Long-Term Effects:
Chronic use or high doses of methylene blue might lead to cumulative side effects, such as prolonged skin discoloration, long-term cognitive changes, or potential neurotoxicity.

Contraindications:

Methylene blue should be used with caution in patients with G6PD deficiency, renal impairment, or those on serotonergic drugs due to the risk of serotonin syndrome.

Patients should be closely monitored for any adverse reactions, especially if they have pre-existing conditions or are taking other medications that might interact with methylene blue.

Note: 

The brand name displayed above is specific to this product. Brand names can vary depending on the manufacturer.