methylene blue; methylthioninium chloride (Provablue, MTC)
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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:
- mild cognitive impairment (investigational)
Adverse effects
- common (> 10%)
- less common (1-10%)
- 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
- do NOT give excessive doses in cyanide poisoning
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
- 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]
More general terms
Additional terms
Component of
- hyoscyamine/methenamine/methylene blue/sodium phosphate
- hyoscyamine/methenamine/methylene blue/phenyl salicylate/sodium phosphate
- hyoscyamine/methenamine/methylene blue/phenyl salicylate
- benzoic acid/hyoscyamine/methenamine/methylene blue/phenyl salicylate
- atropine/benzoic acid/hyoscyamine/methenamine/methylene blue/phenyl salicylate
- hyoscyamine/methenamine/methylene blue/phenyl salicylate/salicylate/sodium phosphate
- benzoate/hyoscyamine/methenamine/methylene blue/phenyl salicylate
- hyoscyamine/methenamine/methylene blue/salicylate/sodium phosphate
- hyoscyamine/methenamine/methylene blue/salicylate
References
- ↑ Drug Information & Medication Formulary, Veterans Affairs, Central California Health Care System, 1st ed., Ravnan et al eds, 1998
- ↑ Kaiser Permanente Northern California Regional Drug Formulary, 1998
- ↑ Department of Veterans Affairs, VA National Formulary
- ↑ 4.0 4.1 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
- ↑ 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
- ↑ 6.0 6.1 Atalla AS, Palka J 12 Causes of Discolored Urine. Medscape. Nov 15, 2017 https://reference.medscape.com/slideshow/discolored-urine-6008332
- ↑ 7.0 7.1 7.2 7.3 Dotinga R Odd Twist in Phase 3 Alzheimer's Trial for Novel Tau Inhibitor. Medscape. December 1, 2022 https://www.medscape.com/viewarticle/984863