Methylene Blue

From Anvita Health Wiki

Contents 1 Indications 2 Dosage 3 Adverse-effects 4 Drug-interactions 5 Mechanism-of-action 6 More General Terms 7 Internet Database 8 References

Indications

• antidote in poisoning due to cyanide & methemoglobinemia
• used in management of patients with oxalate urinary stones
• genitourinary (GU) antiseptic

Dosage

• best if given with vitamin C
• cystitis/ urethritis: 65-130 mg PO TID after meals with water
• renal calculi: 65 mg PO BID- TID after meals with water
• methemoglobinemia:

• 65-130 mg PO TID after meals with water
• 1-2 mg/kg IV; may repeat in 1 hour if necessary

• Injection: 10 mg/mL (10 mL)

Adverse-effects

• common (> 10%)

• discoloration of urine & feces (blue-green)

• less common (1-10%)

• anemia

• uncommon (< 1%)

• hypertension, sweating, dizziness, mental confusion, headache, stains skin, nausea/vomiting, abdominal pain, bladder irritation, precordial pain, fever

• other

• do NOT give excessive doses in cyanide poisoning

• will cause release of cyanide from cyanomethemoglobin

• hemolysis in patients with G6PD deficiency
• hypotension
• diarrhea
• elevated liver function tests ( LFTs)
• dysuria

Drug-interactions

• concurrent use with serotoninergic agents may result in serotonin syndrome [4]

• selective serotonin re-uptake inhibitors ( SSRIs)
• serotonin-norepinephrine re-uptake inhibitors ( SNRIs)
• serotonin agonists
• clomipramine
  

• drug interaction(s) of methylene blue with SNRIs
• drug interaction(s) of methylene blue with SSRIs
• drug interaction(s) of methylene blue with serotonin agonists
• drug interaction(s) of lithium carbonate with phenothiazine
• drug interaction(s) of beta-adrenergic receptor antagonists with phenothiazines

Mechanism-of-action

• dye with antiseptic & dose-dependent redox properties
• reduces methemoglobin in erythrocytes to hemoglobin
• cyanide poisoning: in high doses, oxidizes ferrous iron of reduced hemoglobin to ferric ion, resulting in methemoglobinemia

More General Terms

• pigment
• antidote
• phenothiazine

Internet Database

PubChem: 6099
PubChem: 407237
PubChem: 4139

References

1. Drug Information & Medication Formulary, Veterans Affairs, Central California Health Care System, 1st ed., Ravnan et al eds, 1998
2. Kaiser Permanente Northern California Regional Drug Formulary, 1998
3. Department of Veterans Affairs, VA National Formulary
4. FDA Medwatch - 07/26/2011 Methylene Blue: Drug Safety Communication - Serious CNS Reactions Possible When Given to Patients Taking Certain Psychiatric Medications [1]
5. FDA MedWatch: 10/21/2011 Methylene Blue: Drug Safety Communication - Serious CNS Reactions Possible When Given to Patients Taking Certain Psychiatric Medications [2]

methylene blue