Compound
methylene blue
An organic chloride salt having 3,7-bis(dimethylamino)phenothiazin-5-ium as the counterion. A commonly used dye that also exhibits antioxidant, antimalarial, antidepressant and cardioprotective properties.
Studied for
4 endpoints, 5 findings, from 3 papers.
- Hospital length of staylowersGrade A, Well established. Replicated human trial evidence, consistent direction.
- All-cause mortalitylowersGrade A, Well established. Replicated human trial evidence, consistent direction.
- Intensive care unit length of staylowersGrade A, Well established. Replicated human trial evidence, consistent direction.
- Duration of mechanical ventilationlowersGrade B, Likely. Human evidence, limited replication or design limits.
Structure
- Formula
- C16H18N3S.Cl
- Mass
- 319.861 g/mol
- Charge
- 0
- InChIKey
- CXKWCBBOMKCUKX-UHFFFAOYSA-M
- SMILES
- CN(C)c1ccc2nc3ccc(N(C)C)cc3[s+]c2c1.[Cl-]
- Look it up
- ChEBIBy InChIKey
Identity from ChEBI. Not evidence — none of it carries a grade.
What the evidence says
How to read these marks5 findings across 4 endpoints, from 3 papers, strongest first.
What moved
5 findings
Decreases all-cause mortality
Well establishedGrade A, Well established. Replicated human trial evidence, consistent direction.Finding“We found that MB may reduce short-term mortality in patients with septic shock (RR 0.66 [95% CI, 0.47–0.94]), based on low-certainty evidence, downgraded for imprecision and risk of bias among the included trials.”
Quoted verbatim from Methylene Blue in Septic Shock: A Systematic Review and Meta-Analysis.. - Study
- meta-analysis
- Participants
- 260
- Population
- critically ill adults with septic shock; short-term mortality horizon, longest reported up to 60 d or in-hospital
Effect 0.66 risk ratio, 95% CI 0.47 to 0.94
Methylene Blue in Septic Shock: A Systematic Review and Meta-Analysis.2024PMID:38904978
Decreases intensive care unit length of stay
Well establishedGrade A, Well established. Replicated human trial evidence, consistent direction.Finding“The results showed that MB reduced the ICU LOS in patients with distributive shock (MD: −1.54; 95% CI −2.61 to −0.48; p=0.004; I2=25%; table 2).”
Quoted verbatim from Effect of methylene blue on outcomes in patients with distributive shock: a meta-analysis of randomised controlled trials.. - Study
- meta-analysis
- Participants
- 141
- Population
- adults with distributive shock (septic shock, vasoplegic syndrome, ischaemia-reperfusion injury); secondary endpoint; 3 trials, n = 141
Effect -1.54 mean difference, 95% CI -2.61 to -0.48
Effect of methylene blue on outcomes in patients with distributive shock: a meta-analysis of randomised controlled trials.2024PMID:38216185
Decreases hospital length of stay
Well establishedGrade A, Well established. Replicated human trial evidence, consistent direction.Findingreplicated ×1“The results showed that MB reduced the hospital LOS in patients with distributive shock (MD: −1.97; 95% CI −3.82 to −0.11; p=0.04; table 2).”
Quoted verbatim from Effect of methylene blue on outcomes in patients with distributive shock: a meta-analysis of randomised controlled trials.. - Study
- meta-analysis
- Participants
- 111
- Population
- adults with distributive shock (septic shock, vasoplegic syndrome, ischaemia-reperfusion injury); secondary endpoint; 2 trials, n = 111
Effect -1.97 mean difference, 95% CI -3.82 to -0.11
Effect of methylene blue on outcomes in patients with distributive shock: a meta-analysis of randomised controlled trials.2024PMID:38216185
Decreases duration of mechanical ventilation
LikelyGrade B, Likely. Human evidence, limited replication or design limits.Finding“The results showed that compared with placebo, MB reduced the duration of mechanical ventilation during hospitalisation in patients with distributive shock (MD: −0.68; 95% CI −1.23 to −0.14; p=0.01; I2=0%; online supplemental figure S3).”
Quoted verbatim from Effect of methylene blue on outcomes in patients with distributive shock: a meta-analysis of randomised controlled trials.. - Study
- meta-analysis
- Population
- adults with distributive shock (septic shock, vasoplegic syndrome, ischaemia-reperfusion injury); secondary endpoint; 3 trials
Effect -0.68 mean difference, 95% CI -1.23 to -0.14
Effect of methylene blue on outcomes in patients with distributive shock: a meta-analysis of randomised controlled trials.2024PMID:38216185
Decreases hospital length of stay
LikelyGrade B, Likely. Human evidence, limited replication or design limits.Findingreplicated ×1“Consequently, the mean length of hospital stay was significantly shorter for patients receiving MBI (3.80 ± 0.85 days) than for controls (5.43 ± 1.01 days; P <.001).”
Quoted verbatim from The effect of methylene blue infiltrating injection on anal pain after Milligan-Morgan surgery: A randomized controlled clinical study.. - Study
- RCT
- Participants
- 60
- Dose
- single intraoperative subcutaneous infiltration of 0.5-1 mL of 0.1% methylene blue per incision site, total not exceeding 5 mL
- Population
- adults with mixed haemorrhoids after Milligan-Morgan haemorrhoidectomy; secondary endpoint; reported in days; both arms received the same on-demand intravenous lornoxicam protocol
The effect of methylene blue infiltrating injection on anal pain after Milligan-Morgan surgery: A randomized controlled clinical study.2026PMID:41686620