• Methylene blue is a potential last-line treatment for patients experiencing refractory septic shock. 
  • Limited evidence is available regarding its use as a supplementary treatment in early septic shock, the most effective timing for administration, the ideal dosage, and its safety profile.
  • Surviving Sepsis Campaign guidelines advocate for prompt fluid resuscitation, yet only 50% of patients exhibit a response to fluids, many with temporary vital sign alterations. 
    • Consequently, vasopressors are employed to enhance organ perfusion. Norepinephrine is the primary choice, but elevated doses can lead to complications such as tachyarrhythmia, myocardial dysfunction, peripheral ischemia, and immunosuppression. 
    • Thus, a multi-modal approach to improving organ perfusion can mitigate the potential adverse effects associated with individual therapies.


    • Methylene blue inhibits the inducible nitric oxide synthase and its downstream enzyme soluble guanylate cyclase by restoring vasoregulation in environments with excess nitric oxide, such as sepsis, thereby acting as an indirect “pressor”.

Clinical Question

Does early and repeated administration of methylene blue in patients with septic shock achieve the following outcomes?


18+-year-old patients admitted with septic shock to a Medical ICU in an academic hospital in Mexico.

Septic shock as defined by Sepsis-3 criteria:

    • Highly suspected or confirmed infection
    • Requiring norepinephrine to maintain mean arterial pressure ≥65 mmHg.
    • Serum lactate >2 after adequate fluid resuscitation.
        • Adequate fluid resuscitation defined by administration of at least 500mL bolus of crystalloid followed by negative volume responsiveness with 2+ methods: aortic velocity-time integral after passive leg raising (cut off 10%), arterial pulse pressure variation (cut off 13%), tidal volume challenge (cut of 3.5%), and respiratory variation of carotid peak flow velocity (cut off 14%).



Primary Outcome: Time to vasopressor discontinuation at 28 days

Secondary Outcomes:

    • Vasopressor-free days at 28 days
    • Days on mechanical ventilation
    • Length of Intensive Care Unit (ICU) stay
    • Length of hospital stay
    • Mortality at 28 days


Single-center, double-blinded, randomized control trial

    • Group 1: Sepsis-3 criteria with methylene blue IV 100 mg in 500ml of 0.9% sodium chloride over 6 hrs once daily for 3 days.
    • Group 2: Sepsis-3 criteria with placebo: 500ml of 0.9% sodium chloride for 3 days.
  • After evaluation of 308 patients, 91 patients were included in the study. 
    • 45 patients were assigned to the methylene blue protocol, and 46 were assigned to the placebo protocol.
    • The sample size was powered to 80% and an α-error of 0.05. The study obtained its desired sample size of 88 patients.
  • Patients in both groups received adjunctive vasopressin at 0.03 IU/min if norepinephrine reached greater than or equal to 0.25mcg/kg/min. 
  • Evaluation of volume responsiveness repeated at least 3x per day for the duration of vasopressor utilization. 
  • All patients received Hydrocortisone 200 mg/day via continuous infusion. 
  • Nurse-led vasopressor tapering protocol: norepinephrine titrated at 15-20 min intervals to maintain MAP 65-75. Vasopressin was progressively withdrawn by 0.005 each hour after the complete discontinuation of norepinephrine.


  • Excluded patients with:
    • >24 hours since initiation of norepinephrine
    • Pregnancy
    • High probability of death within 48 hours
    • Concurrent hemorrhagic/obstructive/hypovolemic shock
    • Pending damage control surgery
    • Major burn injury
    • Personal/family hx of glucose-6-phosphate dehydrogenase
    • Allergy to methylene blue, phenothiazines, and food dyes
    • Use of selective serotonin reuptake inhibitors (SSRIs) within 4 weeks 
    • Patient or family refusal
    • Patients testing positive for Covid-19

Primary Results


  • Treatment group (Methylene Blue):
    • Time to vasopressor discontinuation: Shooter time 69 hrs compared to 94 hrs in placebo. p<0.001. 
    • Median difference was 29.4 hrs p<0.001.
    • Vasopressor-free days at 28 days: 1 more day pressor free. p< 0.008.
    • Length of ICU stay: 1.5 day shorter stay p=0.039
    • Length of hospital stay: 2.7 days shorter p=0.027
    • The hazard ratio for shock reversal was 2.7 in the methylene blue group at 28 days p=0.0007.

Adverse Effects:

    • Urine discoloration to green-blue occurred in 93% of the treatment group.
    • Methemoglobin saturation was high in the methylene blue group, 2.9% vs 0.5% p<0.001.


  • Largest randomized control trial, thus far, comparing methylene blue to placebo in septic shock. 
  • Blinded study.
  • Protocol of fluid responsiveness testing, initiation of antibiotics, and vasopressor titration and dosage are all well described and correlate well to standard of care.
  • Minimal study dropout rate.
  • The baseline characteristics of the treatment and placebo group were similar.
  • The use of vasopressors or inotropes other than first-line norepinephrine and second-line vasopressin did not confound the study. 
  • This study’s discussion section thoroughly reviews other relevant randomized control trials on methylene blue and other nitric oxide inhibitors.


  • The study occurred at a single center with only 91 patients, in a Medical ICU in Mexico with a lower-than-average length of ICU and hospital stay compared to the ICUs of other multi-center trials. Thus, further studies may be required to prove external validity. 
  • Patients were, on average, 46 and 47 years old, which may not be generalizable to an aging patient population in other parts of the world. 
  • Patients did not receive an initial 30 cc/kg of volume resuscitation as is considered the current standard of care.
  • Outcomes may not be patient-centered.
  • Relatively higher norepinephrine doses were used compared to other more extensive randomized control trials of patients with septic shock.
  • Due to a high incidence of urine discoloration and elevated methemoglobin levels in the treatment group, identifying the treatment group was highly likely.
  • Patients taking SSRIs were excluded from the study, which is a common medication and often under-reported on medication lists.
  • The total dose and frequency of hydrocortisone patients received is not explicitly stated.
  • The extent to which the data from the member of the control group who died during the trial is integrated into the data set is not explicitly stated.
  • Unclear: The daily weight dose of methylene blue is 1.2mg/kg; however, patients received 100mg of methylene blue in 500 mL of 0.9% sodium chloride.
  • The study was underpowered to conclude mortality trends between groups.

Author's Conclusions

  • Methylene blue administration within 24 hours in septic shock reduces time to vasopressor discontinuation, increases vasopressor-free days at 28 days from diagnosis, and reduces ICU and hospital stay lengths without adverse effects.
  • The findings of this study may shift methylene blue from a rescue therapy to an adjunctive therapy at earlier stages of septic shock. 
  • Other considerations favoring methylene blue are a high safety profile, wide availability, and low cost compared to other catecholamine-sparing agents.

Our Conclusions

Despite the small sample size and study in a single-center ICU in Mexico and possible bias due to patients in the treatment group producing green-blue urine and elevated methemoglobin levels, it is notable that this study is the largest randomized control trial of methylene blue administration in patients with septic shock. This paper thoroughly documents patient assessments, vasopressor titration protocols, and methylene blue dosing. The discussion of this paper is a particular strength as it discusses that methylene blue is an ideal molecule due to its availability, cost, and specificity to inducible nitric oxide. The discussion also comments on how decisions were made on the dose of methylene blue, the timing of dosing, and the repetition of dosing through the reference to several other related studies. Additionally, this study highlights the lack of adverse effects of methylene blue, strengthening the argument for its clinical usage.

Potential Impact To Current Practice

Despite its limitations, this high-quality study should prompt further research toward considering methylene blue as an early adjuvant tool when managing patients in septic shock, preferably using patient-centered outcomes.