Methylene Blue

Methylene blue is a water soluble thiazine dye that promotes a non-enzymatic redox conversion of metHb to hemoglobin. In situ, methylene blue is first converted to leucomethylene blue (LMB) via NADPH reductase.

• Methylene Blue Injection is indicated for the treatment of pediatric and adult patients with acquired methemoglobinemia. Methylene Blue Injection is an oxidation-reduction agent indicated for the treatment of pediatric and adult patients with acquired methemoglobinemia.

• Methylene blue injection is contraindicated in the following conditions: Severe hypersensitivity reactions to methylene blue or any other thiazine dye [see Warnings and Precautions (5.2) ] . Patients with glucose-6-phosphate dehydrogenase deficiency (G6PD) due to the risk of hemolytic anemia [see Warnings and Precautions (5.3 , 5.4 )] .contraindicated

Administer 1 mg/kg intravenously over 5-30 minutes. ( 2.1 ) If methemoglobin level remains above 30% or if clinical symptoms persist, give a repeat dose of up to 1 mg/kg one hour after the first dose. ( 2.1 ) Administer a single dose of 1 mg/kg in patients with moderate or severe renal impairment. ( 2.2 ) 2.1 Dosage and Administration Ensure patent venous access prior to administration of methylene blue injection. Do not administer methylene blue injection subcutaneously. Administer methylene blue injection 1 mg/kg intravenously over 5-30 minutes. If the methemoglobin level remains greater than 30% or if clinical signs and symptoms persist, a repeat dose of methylene blue injection 1 mg/kg may be given one hour after the first dose. If methemoglobinemia does not resolve after 2 doses of methylene blue injection, consider initiating alternative interventions for treatment of methemoglobinemia. 2.2 Recommended Dosage for Renal Impairment The recommended dosage of methylene blue injection in patients with moderate or severe renal impairment (eGFR 15-59 mL/min/1.73 m 2 ) is a single dose of 1 mg/kg. If the methemoglobin level remains greater than 30% or if the clinical symptoms persist 1 hour after dosing, consider initiating alternative interventions for the treatment of methemoglobinemia. 2.3 Preparation Methylene blue injection is hypotonic and may be diluted before use in a solution of 50 mL 5% Dextrose Injection in order to avoid local pain, particularly in the pediatric population. Use the diluted solution immediately after preparation.

Hypersensitivity: If severe or life threatening allergic reaction occurs, discontinue methylene blue injection, treat the allergic reaction, and monitor until signs and symptoms resolve. ( 5.2 ) Lack of Effectiveness: Consider alternative treatments if there is no resolution of methemoglobinemia after 2 doses. ( 2.1 , 5.3 ) Hemolytic Anemia: Discontinue methylene blue injection and transfuse. ( 5.4 ) Interference with In Vivo Monitoring Devices: Use methods other than pulse oximetry to assess oxygen saturation. ( 5.5 ) Effects on Ability to Drive and Operate Machinery: Advise patients to refrain from these activities until neurologic and visual symptoms have resolved. ( 5.6 ) 5.1 Serotonin Syndrome with Concomitant Use of Serotonergic Drugs and Opioids The development of serotonin syndrome has been reported with the use of methylene blue class products. Most reports have been associated with concomitant use of serotonergic drugs (e.g., selective serotonin reuptake inhibitors (SSRIs), serotonin and norepinephrine reuptake inhibitors (SNRIs), monoamine oxidase inhibitors (MAOIs)). Opioids and dextromethorphan may increase the risk of developing serotonin syndrome. Some of the reported cases were fatal.

The following adverse reactions are discussed in greater detail in other sections of the labeling: Serotonin Syndrome with Concomitant Use of Serotonergic Drugs [see Warnings and Precautions (5.1) ] Anaphylaxis [see Warnings and Precautions (5.2) ] Lack of Effectiveness [see Warnings and Precautions (5.3) ] Hemolytic Anemia [see Warnings and Precautions (5.4) ] Interference with In Vivo Monitoring Devices [see Warnings and Precautions (5.5) ] Effects on Ability to Drive and Operate Machinery [see Warnings and Precautions (5.6) ] Interference with Laboratory Tests [see Warnings and Precautions (5.7) ] The most commonly reported adverse reactions (≥2%) included headache, hypokalemia, diarrhea, hypomagnesemia, myoclonus, nausea, and seizure-like phenomena. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Meitheal Pharmaceuticals Inc. at 1-844-824-8426 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch . 6.1 Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice. The safety of methylene blue injection in adults with acquired methemoglobinemia was assessed in 24 patients who received at least 1 dose of methylene blue injection [see Clinical Studies (14) ] . Most doses administered were 1 mg/kg (88.5%), but doses from 1 mg/kg to 2 mg/kg were administered.

Pregnancy: Only use during pregnancy if the potential benefit justifies the potential risk to the fetus. ( 8.1 ) Lactation: Discontinue breast-feeding for up to 8 days after treatment. ( 8.2 ) Hepatic Impairment: Monitor patients longer for toxicity and drug interactions due to delayed clearance. ( 8.7 ) 8.1 Pregnancy Risk Summary Methylene blue injection may cause fetal harm when administered to a pregnant woman. Intra-amniotic injection of pregnant women with a methylene blue class product during the second trimester was associated with neonatal intestinal atresia and fetal death. Methylene blue produced adverse developmental outcomes in rats and rabbits when administered orally during organogenesis at doses at least 32 and 16 times, respectively, the clinical dose of 1 mg/kg ( see Data ) . Advise pregnant women of the potential risk to a fetus. In the U.S. general population, the estimated background risks of major birth defects and miscarriage in clinically recognized pregnancies are 2-4% and 15-20%, respectively. Clinical Considerations Fetal/neonatal adverse reactions Intra-amniotic injection of a methylene blue class product hours to days prior to birth can result hyperbilirubinemia, hemolytic anemia, skin staining, methemoglobinemia, respiratory distress and photosensitivity in the newborn.

Metabolism

The mean (CV%) C max and AUC of methylene blue 2,917 ng/mL (39%) and 13,977 ng•hr/mL (21%) following a 2 mg/kg dose administered as a 5-minute intravenous infusion. Distribution The mean± standard deviation steady state volume of distribution of a 2 mg/kg dose of methylene blue injection was 255 L ± 58.

Hypotension, wheezing and reduced oxygenation have been reported in patients who received methylene blue class products in single doses of 3 mg/kg or more. Administration of large intravenous doses (cumulative dose ≥ 7 mg/kg) of a methylene blue class product caused nausea, vomiting, precordial pain, dyspnea, tachypnea, chest tightness, tachycardia, apprehension, tremor, mydriasis, blue staining of the urine, the skin and mucous membranes, abdominal pain, dizziness, paresthesia, headache, confusion, mild methemoglobinemia (up to 7%) and electrocardiogram changes (T-wave flattening or inversion). These effects lasted 2-12 hours following administration. A severe overdosage (single dose of 20 mg/kg or more) of a methylene blue class product caused severe intravascular hemolysis, hyperbilirubinemia and death. In case of overdose of methylene blue injection, maintain the patient under observation until signs and symptoms have resolved, monitor for cardiopulmonary, hematologic and neurologic toxicities, and institute supportive measures as necessary.

• Apr 8, 2016NDANDA204630Provepharm Sas
• Dec 5, 2023ANDAANDA215636Zydus Lifesciences
• Nov 21, 2024ANDAANDA217561Nexus
• Nov 22, 2024ANDAANDA216955Steriscience
• Dec 17, 2024ANDAANDA216959Hikma
• Jan 23, 2025ANDAANDA217380Meitheal
• Jul 30, 2025ANDAANDA219363Xiromed
• Dec 23, 2025ANDAANDA219550Chengdu Shuode

1. 1Serotonin Syndrome46427%
2. 2Drug Interaction35721%
3. 3Drug Ineffective30918%
4. 4Hypotension20512%
5. 5Off Label Use20312%
6. 6Toxicity To Various Agents1357.8%
7. 7Overdose1035.9%
8. 8Intentional Overdose985.6%
9. 9Encephalopathy834.8%
10. 10Toxic Encephalopathy764.4%
11. 11Acute Kidney Injury754.3%
12. 12Confusional State754.3%
13. 13Blood Creatine Phosphokinase Increased734.2%
14. 14Vasoplegia Syndrome704.0%
15. 15Alanine Aminotransferase Increased683.9%

Recent PubMed references pinned to Methylene Blue as a MeSH major topic. Citations link to pubmed.ncbi.nlm.nih.gov.

• Synergic effect of dielectric barrier discharge plasma and hydrodynamic cavitation on decolorization of methylene blue.
  PloS one · 2026 · Ahadi A, Zali A, Ghorbanalilu M, et al.
  PMID 42258442DOI 10.1371/journal.pone.0348118
• Acid Yellow 36, Methyl Red, and Methylene Blue adsorption using ammonia-modified red algae biochar: isotherm, kinetic, regeneration, and ANN studies.
  Scientific reports · 2026 · Hassaan MA, Yılmaz M, Sikaily AE, et al.
  PMID 42236514DOI 10.1038/s41598-026-55117-4
• A sustainable bio-adsorbent from cork oak leaves for methylene blue removal: RSM-BBD optimization, regeneration, DFT/MD insights, and contributions to the SDGs.
  Scientific reports · 2026 · Meftah S, Chahid A, Meftah K, et al.
  PMID 42225641DOI 10.1038/s41598-026-45233-6
• Methylene Blue for Prevention of Perioperative Neurocognitive Disorders: Mechanisms and Recent Clinical Evidence.
  Drug design, development and therapy · 2026 · Wu Y, Wang J, Wan X, et al.
  PMID 42206236DOI 10.2147/DDDT.S602971
• Dealumination of 3D-printed geopolymers for enhanced methylene blue removal from wastewater.
  Journal of environmental management · 2026 · Caetano APF, Gonçalves NPF, Labrincha JA, et al.
  PMID 42167163DOI 10.1016/j.jenvman.2026.129995
• Potential molecular targets on which methylene blue acts to promote its effects on cardiac electrophysiology, myocardial injury, and oxidative stress in spontaneously hypertensive rats submitted to cardiac ischemia and reperfusion.
  Acta cirurgica brasileira · 2026 · Lima RY, Govato TCP, Araújo EA, et al.
  PMID 42154898DOI 10.1590/acb411826
• Systematic assessment of methylene blue removal by Co-N/C nanofibers: key factors, degradation pathways, DFT study and toxicity evaluation.
  Environmental research · 2026 · Wang M, Zhang H, Song Y, et al.
  PMID 42142573DOI 10.1016/j.envres.2026.124714
• Adsorptive removal of methylene blue from wastewater using sawdust of Cedrus deodara and its composite with iron oxide nanoparticles: a comparative study.
  Environmental science and pollution research international · 2026 · Shakeel M, Ali S, Waseem M, et al.
  PMID 42141228DOI 10.1007/s11356-026-37841-6

The 10 most recently updated of 335 ClinicalTrials.gov registrations naming Methylene Blue as an intervention. Registration is not evidence of efficacy or safety — reference crosswalk only.

• Assessing the Efficacy of Photodynamic Therapy for Preventing Surgical Site Infections
  Recruiting · Interventional · 80 enrolled · Guy's and St Thomas' NHS Foundation Trust
  NCT06731881updated 2026-06-11
• Identification of Sentinel Lymph Nodes With Methylene Blue and Isotope
  Completed · Interventional · 100 enrolled · University Hospital, Strasbourg, France
  NCT00314405updated 2026-06-08
• Use of Sentinel Lymph Node Biopsy in Patients With Early-Stage, Palpable Node-Positive HR+/HER2- Breast Cancer Having Upfront Surgery and Adjuvant Radiation
  Active not recruiting · Observational · 78 enrolled · Memorial Sloan Kettering Cancer Center
  NCT04854005updated 2026-05-29
• Bariatric Endoscopic Antral Myotomy Combined With Fundal Gastric Mucosal Ablation
  Not yet recruiting · Phase 2 · Interventional · 10 enrolled · Cairo University
  NCT07612527updated 2026-05-28
• Topical Methylene Blue-Photodynamic Therapy (MB-PDT) for Burn Wound Infection
  Not yet recruiting · Early phase 1 · Interventional · 50 enrolled · University of Oklahoma
  NCT07494773updated 2026-05-19
• Laparoscopic Single Anastomosis Sleeve Ileal Bypass Versus Laparoscopic Sleeve Gastrectomy for Morbid Obesity
  Recruiting · Interventional · 220 enrolled · Oslo University Hospital
  NCT05611697updated 2026-05-18
• Intravenous Versus Perineural Ondansetron for Laparoscopic Sleeve Gastrectomy
  Recruiting · Interventional · 482 enrolled · Tanta University
  NCT06810882updated 2026-05-15
• Comparison of Efficacy and Safety Between Methylene Blue-mediated Photodynamic Therapy and 5% Amorolfine Nail Lacquer for Toenail Onychomycosis Treatment
  Completed · Interventional · 27 enrolled · Chulalongkorn University
  NCT03098342updated 2026-05-13
• Efficacy of Methylene Blue Mediated Photodynamic Therapy for Primary Localized Cutaneous Amyloidosis Treatment in Asians
  Completed · Interventional · 15 enrolled · Chulalongkorn University
  NCT03068208updated 2026-05-13
• Light-Activated Antimicrobial Therapy to Prevent Surgical Site Infections - Canada
  Completed · Interventional · 401 enrolled · Ondine Biomedical Inc.
  NCT07189858updated 2026-05-12

CPIC-curated drug–gene pairs for Methylene Blue. Levels describe the strength of curated evidence and guideline status — never a recommendation to test or to adjust therapy.

• G6PDCPIC AClinPGx 3FDA label: Actionable PGx
  G6PD

Frequently asked questions

How does Methylene Blue work?

Methylene blue is a water soluble thiazine dye that promotes a non-enzymatic redox conversion of metHb to hemoglobin. In situ, methylene blue is first converted to leucomethylene blue (LMB) via NADPH reductase.

What is Methylene Blue used for?

According to FDA labeling, Methylene Blue carries indications including: Methylene Blue Injection is indicated for the treatment of pediatric and adult patients with acquired methemoglobinemia. Methylene Blue Injection is an oxidation-reduction agent indicated for the treatment of pediatric and adult patients with acquired methemoglobinemia.. This is a reference summary of labeled uses, not medical advice or a treatment recommendation.

What class of drug is Methylene Blue?

Methylene Blue is classified as Antidotes, Tests for gastric secretion, Alkylating Activity, Binding Activity, Cellular Activity Alteration, Increased Metabolic Rate, Oxygen Carrying Capacity Alteration.

What are the brand names for Methylene Blue?

Methylene Blue is marketed under brand names including Hyophen, Phosphasal, Prosed DS, Provayblue, Urelle, Uretron DS, Uribel, Uribel Tabs.

What are the contraindications for Methylene Blue?

Methylene Blue labeling lists contraindications including: Methylene blue injection is contraindicated in the following conditions: Severe hypersensitivity reactions to methylene blue or any other thiazine dye [see Warnings and Precautions (5.2) ] . Patients with glucose-6-phosphate dehydrogenase deficiency (G6PD) due to the risk of hemolytic anemia [see Warnings and Precautions (5.3 , 5.4 )] .. Always consult the full prescribing information and a clinician.