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methylene blue; methylthioninium chloride (Provablue, MTC)

Indications: 1) antidote in poisoning due to cyanide & methemoglobinemia 2) used in management of patients with oxalate urinary stones 3) genitourinary (GU) antiseptic Dosage: 1) best if given with vitamin C 2) cystitis/urethritis: 65-130 mg PO TID after meals with water 3) renal calculi: 65 mg PO BID-TID after meals with water 4) methemoglobinemia: a) 65-130 mg PO TID after meals with water b) 1-2 mg/kg IV; may repeat in 1 hour if necessary 5) mild cognitive impairment (investigational) - 8 mg PO weekly showed benefit [7] Injection: 10 mg/mL (10 mL) Adverse effects: 1) common (> 10%) - discoloration of urine & feces (blue-green) [6] 2) less common (1-10%) - anemia 3) uncommon (< 1%) - hypertension, sweating, dizziness, mental confusion, headache, stains skin, nausea/vomiting, abdominal pain, bladder irritation, precordial pain, fever 4) other a) do NOT give excessive doses in cyanide poisoning - will cause release of cyanide from cyanomethemoglobin b) hemolysis in patients with G6PD deficiency c) hypotension d) diarrhea e) elevated liver function tests (LFTs) f) dysuria Drug interactions: - concurrent use with serotoninergic agents may result in serotonin syndrome [4] a) selective serotonin re-uptake inhibitors (SSRIs) b) serotonin-norepinephrine re-uptake inhibitors (SNRIs) c) serotonin agonists d) clomipramine Mechanism of action: 1) dye with antiseptic & dose-dependent redox properties 2) reduces methemoglobin in erythrocytes to hemoglobin 3) cyanide poisoning: in high doses, oxidizes ferrous iron of reduced hemoglobin to ferric ion, resulting in methemoglobinemia 4) experimental oral tau aggregation inhibitor Clinical trials: - used as a control for hydromethylthionine mesylate in the Alzheimer's Disease Study LUCIDITY [7] * control group receiving methylthioninium chloride as an agent to dicolor urine in the placebo also showed cognitive improvement [7]

Interactions

drug interactions

Related

hydromethylthionine mesylate; leucomethylene blue dimesylate (HMTM) methylene blue staining microscopic observation in tissue by methylene blue stain

General

antidote phenothiazine pigment tau aggregation inhibitor

Properties

MISC-INFO: elimination route KIDNEY pregnancy-category C safety in lactation ?

Database Correlations

PUBCHEM correlations

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 http://www.fda.gov/Safety/MedWatch/SafetyInformation/SafetyAlertsforHumanMedicalProducts/ucm265476.htm
  5. FDA MedWatch: 10/21/2011 Methylene Blue: Drug Safety Communication - Serious CNS Reactions Possible When Given to Patients Taking Certain Psychiatric Medications http://www.fda.gov/Safety/MedWatch/SafetyInformation/SafetyAlertsforHumanMedicalProducts/ucm265476.htm
  6. Atalla AS, Palka J 12 Causes of Discolored Urine. Medscape. Nov 15, 2017 https://reference.medscape.com/slideshow/discolored-urine-6008332
  7. Dotinga R Odd Twist in Phase 3 Alzheimer's Trial for Novel Tau Inhibitor. Medscape. December 1, 2022 https://www.medscape.com/viewarticle/984863

Component-of

atropine/benzoic acid/hyoscyamine/methenamine/methylene blue/phenyl salicylate benzoate/hyoscyamine/methenamine/methylene blue/phenyl salicylate benzoic acid/hyoscyamine/methenamine/methylene blue/phenyl salicylate hyoscyamine/methenamine/methylene blue/phenyl salicylate hyoscyamine/methenamine/methylene blue/phenyl salicylate/salicylate/sodium phosphate hyoscyamine/methenamine/methylene blue/phenyl salicylate/sodium phosphate hyoscyamine/methenamine/methylene blue/salicylate hyoscyamine/methenamine/methylene blue/salicylate/sodium phosphate hyoscyamine/methenamine/methylene blue/sodium phosphate