Methylene Blue 20mg/2ml Pf Syr, 2ml
WARNING: A severe and sometimes deadly problem called serotonin syndrome may happen if you take this drug with certain other drugs. Call your doctor right away if you have agitation; change in balance; confusion; hallucinations; fever; fast or abnormal heartbeat; flushing; muscle twitching or stiffness; seizures; shivering or shaking; sweating a lot; severe diarrhea, upset stomach, or throwing up; or severe headache.Some drugs may raise the risk of serotonin syndrome when taken with this drug. Certain drugs must not be taken with this drug or within 72 hours after stopping this drug. Talk with your doctor if you take any drugs (prescription or OTC, natural products, vitamins) that must not be taken with this drug, like certain drugs that are used for depression, other mental or mood problems, or migraine headaches. There are many drugs that must not be taken with this drug or for some time before this drug is started. Ask your doctor or pharmacist. @ COMMON USES: It is used to treat methemoglobinemia. It may be given to you for other reasons. Talk with the doctor.
Drug Class
Antidote
Pharmacologic Class
Methemoglobinemia agent; Diagnostic agent
Pregnancy Category
Category X
FDA Approved
Jul 1986
DEA Schedule
Not Controlled
Overview
What is this medicine?
Methylene blue is a medication given by injection, usually into a vein, to treat a condition where your blood can't carry enough oxygen, called methemoglobinemia. It helps your red blood cells carry oxygen properly again. It can also be used for certain diagnostic tests. A common side effect is that it will turn your urine and sometimes your skin a blue-green color.
How to Use This Medicine
Taking Your Medication
To use this medication correctly, follow your doctor's instructions and read all the information provided. Administer the medication as directed, which typically involves intravenous infusion over a specified period. It is essential to note that this medication should only be given into a vein and never into the spinal canal or subcutaneous tissue (the fatty layer under the skin).
Storing and Disposing of Your Medication
If you need to store this medication at home, consult with your doctor, nurse, or pharmacist for guidance on proper storage procedures.
Missing a Dose
If you miss a dose, contact your doctor promptly to determine the best course of action.
To use this medication correctly, follow your doctor's instructions and read all the information provided. Administer the medication as directed, which typically involves intravenous infusion over a specified period. It is essential to note that this medication should only be given into a vein and never into the spinal canal or subcutaneous tissue (the fatty layer under the skin).
Storing and Disposing of Your Medication
If you need to store this medication at home, consult with your doctor, nurse, or pharmacist for guidance on proper storage procedures.
Missing a Dose
If you miss a dose, contact your doctor promptly to determine the best course of action.
Lifestyle & Tips
- Avoid taking any other medications, especially antidepressants or migraine medications, without consulting your doctor, as serious interactions can occur.
- Inform all healthcare providers that you have received methylene blue, as it can interfere with certain lab tests (e.g., pulse oximetry).
Available Forms & Alternatives
Dosing & Administration
Adult Dosing
Standard Dose:
1 to 2 mg/kg IV over 5 minutes
Dose Range:
1 - 2 mg
Condition-Specific Dosing:
methemoglobinemia:
1 to 2 mg/kg IV over 5 minutes. May repeat dose of 1 mg/kg 1 hour after initial dose if methemoglobin level remains elevated or clinical signs/symptoms persist. Max cumulative dose: 7 mg/kg.
Pediatric Dosing
Neonatal:
0.5 to 1 mg/kg IV over 5 minutes for methemoglobinemia. May repeat dose of 0.5 mg/kg 1 hour after initial dose if methemoglobin level remains elevated or clinical signs/symptoms persist. Max cumulative dose: 7 mg/kg.
Infant:
1 to 2 mg/kg IV over 5 minutes for methemoglobinemia. May repeat dose of 1 mg/kg 1 hour after initial dose if methemoglobin level remains elevated or clinical signs/symptoms persist. Max cumulative dose: 7 mg/kg.
Child:
1 to 2 mg/kg IV over 5 minutes for methemoglobinemia. May repeat dose of 1 mg/kg 1 hour after initial dose if methemoglobin level remains elevated or clinical signs/symptoms persist. Max cumulative dose: 7 mg/kg.
Adolescent:
1 to 2 mg/kg IV over 5 minutes for methemoglobinemia. May repeat dose of 1 mg/kg 1 hour after initial dose if methemoglobin level remains elevated or clinical signs/symptoms persist. Max cumulative dose: 7 mg/kg.
Dose Adjustments
Renal Impairment:
Mild:
No specific adjustment recommended, use with caution.
Moderate:
Use with caution; consider lower doses or extended dosing intervals due to potential for accumulation and toxicity.
Severe:
Contraindicated due to risk of accumulation and toxicity.
Dialysis:
Not dialyzable. Contraindicated.
Hepatic Impairment:
Mild:
No specific adjustment recommended, use with caution.
Moderate:
Use with caution; consider lower doses or extended dosing intervals.
Severe:
Use with caution; consider lower doses or extended dosing intervals due to potential for accumulation and toxicity.
Pharmacology
Mechanism of Action
Methylene blue acts as an electron acceptor for NADPH-methemoglobin reductase (NADPH-dependent methemoglobin reductase). In this reaction, methylene blue is reduced to leucomethylene blue, which then reduces ferric iron (Fe3+) in methemoglobin to ferrous iron (Fe2+) in hemoglobin. This restores the oxygen-carrying capacity of hemoglobin. At high concentrations, methylene blue can paradoxically induce methemoglobinemia by oxidizing ferrous iron to ferric iron.
Pharmacokinetics
Absorption:
Bioavailability:
Not available (IV administration)
Tmax:
Not available (IV administration)
FoodEffect:
Not applicable (IV administration)
Distribution:
Vd:
2.7 L/kg
ProteinBinding:
Not available
CnssPenetration:
Limited
Elimination:
HalfLife:
5 to 24 hours (variable, mean ~19 hours)
Clearance:
Not available
ExcretionRoute:
Renal (primarily), some biliary
Unchanged:
Approximately 75% excreted unchanged in urine, imparting a blue-green color.
Pharmacodynamics
OnsetOfAction:
Within 30 minutes
PeakEffect:
1 hour
DurationOfAction:
Several hours (effect on methemoglobin levels)
Confidence:
Medium
Safety & Warnings
BLACK BOX WARNING
Risk of Serotonin Syndrome when used with serotonergic drugs. Risk of Hemolytic Anemia in patients with G6PD deficiency.
Side Effects
Urgent Side Effects: Seek Medical Help Right Away
Although rare, some people may experience severe and potentially life-threatening side effects while taking this medication. If you notice any of the following symptoms, contact your doctor or seek immediate medical attention:
Signs of an allergic reaction, such as:
+ Rash
+ Hives
+ Itching
+ Red, swollen, blistered, or peeling skin with or without fever
+ Wheezing
+ Tightness in the chest or throat
+ Trouble breathing, swallowing, or talking
+ Unusual hoarseness
+ Swelling of the mouth, face, lips, tongue, or throat
Signs of electrolyte problems, including:
+ Mood changes
+ Confusion
+ Muscle pain, cramps, or spasms
+ Weakness
+ Shakiness
+ Change in balance
+ Abnormal heartbeat
+ Seizures
+ Loss of appetite
+ Severe upset stomach or vomiting
Dizziness or fainting
Confusion
Changes in vision
Feeling extremely tired or weak
Pale skin
Dark urine or yellowing of the skin or eyes
Seizures
Other Possible Side Effects
Like all medications, this drug can cause side effects. While many people may not experience any side effects or only minor ones, it's essential to discuss any concerns with your doctor. If you experience any of the following side effects or any other unusual symptoms, contact your doctor for advice:
Urine or stool turning blue or green (this is a normal and harmless effect)
Skin turning blue-green
Pain, redness, or swelling at the injection site
Diarrhea or stomach upset
Headache
Reporting Side Effects
This list is not exhaustive, and you may experience other side effects. If you have questions or concerns, contact your doctor. You can also report side effects to the FDA at 1-800-332-1088 or online at https://www.fda.gov/medwatch.
Although rare, some people may experience severe and potentially life-threatening side effects while taking this medication. If you notice any of the following symptoms, contact your doctor or seek immediate medical attention:
Signs of an allergic reaction, such as:
+ Rash
+ Hives
+ Itching
+ Red, swollen, blistered, or peeling skin with or without fever
+ Wheezing
+ Tightness in the chest or throat
+ Trouble breathing, swallowing, or talking
+ Unusual hoarseness
+ Swelling of the mouth, face, lips, tongue, or throat
Signs of electrolyte problems, including:
+ Mood changes
+ Confusion
+ Muscle pain, cramps, or spasms
+ Weakness
+ Shakiness
+ Change in balance
+ Abnormal heartbeat
+ Seizures
+ Loss of appetite
+ Severe upset stomach or vomiting
Dizziness or fainting
Confusion
Changes in vision
Feeling extremely tired or weak
Pale skin
Dark urine or yellowing of the skin or eyes
Seizures
Other Possible Side Effects
Like all medications, this drug can cause side effects. While many people may not experience any side effects or only minor ones, it's essential to discuss any concerns with your doctor. If you experience any of the following side effects or any other unusual symptoms, contact your doctor for advice:
Urine or stool turning blue or green (this is a normal and harmless effect)
Skin turning blue-green
Pain, redness, or swelling at the injection site
Diarrhea or stomach upset
Headache
Reporting Side Effects
This list is not exhaustive, and you may experience other side effects. If you have questions or concerns, contact your doctor. You can also report side effects to the FDA at 1-800-332-1088 or online at https://www.fda.gov/medwatch.
Seek Immediate Medical Attention If You Experience:
- Severe headache
- Confusion or agitation
- High fever
- Muscle stiffness or twitching
- Rapid heart rate
- Sweating
- Dark urine (beyond the expected blue-green color)
- Yellowing of skin or eyes (jaundice)
- Unusual tiredness or weakness
Before Using This Medicine
Before Taking This Medication: Important Information to Share with Your Doctor
It is essential to inform your doctor about the following:
Any allergies you have, including allergies to this medication, its components, or other substances. Be sure to describe the allergic reaction you experienced, including the symptoms that occurred.
If you have a condition called G6PD deficiency.
If you are pregnant or think you might be pregnant. This medication may pose a risk to the unborn baby, so it is crucial to discuss the potential benefits and risks with your doctor to determine if this medication is suitable for you.
If you are breastfeeding. You should not breastfeed while taking this medication or for 8 days after your last dose.
This list is not exhaustive, and it is vital to disclose all your medications (including prescription, over-the-counter, natural products, and vitamins) and health issues to your doctor and pharmacist. They will help you verify that it is safe to take this medication in conjunction with your other medications and health conditions. Never start, stop, or adjust the dosage of any medication without first consulting your doctor.
It is essential to inform your doctor about the following:
Any allergies you have, including allergies to this medication, its components, or other substances. Be sure to describe the allergic reaction you experienced, including the symptoms that occurred.
If you have a condition called G6PD deficiency.
If you are pregnant or think you might be pregnant. This medication may pose a risk to the unborn baby, so it is crucial to discuss the potential benefits and risks with your doctor to determine if this medication is suitable for you.
If you are breastfeeding. You should not breastfeed while taking this medication or for 8 days after your last dose.
This list is not exhaustive, and it is vital to disclose all your medications (including prescription, over-the-counter, natural products, and vitamins) and health issues to your doctor and pharmacist. They will help you verify that it is safe to take this medication in conjunction with your other medications and health conditions. Never start, stop, or adjust the dosage of any medication without first consulting your doctor.
Precautions & Cautions
It is essential to inform all your healthcare providers, including doctors, nurses, pharmacists, and dentists, that you are taking this medication. Regular monitoring is crucial, so be sure to undergo blood work, other laboratory tests, blood pressure checks, and heart rate assessments as directed by your doctor. Additionally, you will need to have your heart rhythm checked with an electrocardiogram (ECG) as scheduled.
Please note that this medication may interfere with certain laboratory tests. Therefore, it is vital to disclose that you are taking this drug to all your healthcare providers and laboratory personnel.
To ensure your safety, avoid operating a vehicle or engaging in activities that require alertness until you are aware of how this medication affects you. You may be more susceptible to sunburn, so it is recommended to limit your exposure to the sun, sunlamps, and tanning beds. When going outside, protect yourself from the sun by using sunscreen and wearing protective clothing and eyewear.
Please note that this medication may interfere with certain laboratory tests. Therefore, it is vital to disclose that you are taking this drug to all your healthcare providers and laboratory personnel.
To ensure your safety, avoid operating a vehicle or engaging in activities that require alertness until you are aware of how this medication affects you. You may be more susceptible to sunburn, so it is recommended to limit your exposure to the sun, sunlamps, and tanning beds. When going outside, protect yourself from the sun by using sunscreen and wearing protective clothing and eyewear.
Overdose Information
Overdose Symptoms:
- Nausea
- Vomiting
- Diarrhea
- Abdominal pain
- Headache
- Dizziness
- Confusion
- Cyanosis (blue discoloration of skin/lips)
- Methemoglobinemia (paradoxical increase)
- Hemolytic anemia
- Cardiac arrhythmias
- Hypertension
What to Do:
Seek immediate medical attention. Call 911 or Poison Control at 1-800-222-1222. Treatment is supportive and may include oxygen, IV fluids, and in severe cases, exchange transfusion or other antidotes depending on the specific symptoms (e.g., for severe methemoglobinemia).
Drug Interactions
Contraindicated Interactions
- Serotonergic drugs (e.g., SSRIs, SNRIs, TCAs, MAOIs, triptans, buspirone, tramadol, fentanyl, St. John's Wort) due to risk of serotonin syndrome.
- Patients with G6PD deficiency (risk of hemolytic anemia).
- Patients with severe renal impairment.
Major Interactions
- Other methemoglobin-inducing agents (e.g., dapsone, nitrates, local anesthetics) - may exacerbate methemoglobinemia.
- Drugs that prolong QT interval (theoretical risk, monitor ECG).
Moderate Interactions
- Anticoagulants (e.g., warfarin) - may interfere with INR monitoring (false low INR).
- Drugs metabolized by CYP450 enzymes (e.g., CYP2D6 substrates) - methylene blue is a potent inhibitor of several CYP enzymes.
Minor Interactions
- Not available
Monitoring
Baseline Monitoring
Methemoglobin level
Rationale: To confirm diagnosis and establish baseline severity of methemoglobinemia.
Timing: Prior to administration
Pulse oximetry (SpO2)
Rationale: To assess oxygen saturation; note that methylene blue can cause a spurious drop in SpO2.
Timing: Prior to administration
Arterial blood gas (ABG)
Rationale: To assess oxygenation and acid-base status.
Timing: Prior to administration
G6PD deficiency screen
Rationale: To rule out G6PD deficiency, a contraindication due to risk of hemolytic anemia.
Timing: Prior to administration (if time permits and status unknown)
Renal function (BUN, creatinine)
Rationale: To assess kidney function, as severe renal impairment is a contraindication.
Timing: Prior to administration
Routine Monitoring
Methemoglobin level
Frequency: 1 hour after dose, then as clinically indicated
Target: <2% or resolution of symptoms
Action Threshold: >10% or persistent symptoms after initial dose, consider repeat dose
Clinical signs and symptoms (e.g., cyanosis, dyspnea, altered mental status)
Frequency: Continuously
Target: Resolution of symptoms
Action Threshold: Worsening or persistence of symptoms
Pulse oximetry (SpO2) and co-oximetry
Frequency: Continuously
Target: Improving SpO2, accurate SaO2 by co-oximetry
Action Threshold: Persistent low SpO2 despite supplemental oxygen, or discrepancy between SpO2 and SaO2
Hemoglobin, hematocrit, signs of hemolysis
Frequency: Daily or as clinically indicated
Target: Stable
Action Threshold: Significant drop in Hgb/Hct, signs of hemolysis (e.g., dark urine, jaundice)
Symptom Monitoring
- Cyanosis (especially of lips, nail beds)
- Dyspnea
- Headache
- Dizziness
- Fatigue
- Confusion
- Tachycardia
- Chest pain
- Nausea
- Abdominal pain
- Serotonin syndrome symptoms (agitation, hyperthermia, rigidity, hyperreflexia, clonus, diaphoresis, tremor)
- Hemolytic anemia symptoms (dark urine, jaundice, pallor, fatigue)
Special Patient Groups
Pregnancy
Contraindicated in pregnancy (Category X). Methylene blue can cause fetal harm, including hemolytic anemia and hyperbilirubinemia, particularly in G6PD deficient fetuses. It has been associated with adverse outcomes when used during pregnancy, especially in the third trimester.
Trimester-Specific Risks:
First Trimester:
Potential for fetal harm, avoid.
Second Trimester:
Potential for fetal harm, avoid.
Third Trimester:
High risk of fetal hemolytic anemia and hyperbilirubinemia, especially if fetus is G6PD deficient. Contraindicated.
Lactation
Contraindicated during breastfeeding (L5). Methylene blue is excreted into breast milk and can cause serious adverse reactions in a breastfed infant, including hemolytic anemia, especially in infants with G6PD deficiency. Breastfeeding should be discontinued during treatment and for at least 8 days after the last dose.
Infant Risk:
High risk of hemolytic anemia, hyperbilirubinemia, and other adverse effects.
Pediatric Use
Use with caution, especially in neonates and infants, due to increased susceptibility to methemoglobinemia and hemolytic anemia. Dosing should be carefully calculated based on weight. Contraindicated in neonates with G6PD deficiency.
Geriatric Use
Use with caution. Elderly patients may have reduced renal function, increasing the risk of accumulation and adverse effects. Start with lower doses and monitor closely for toxicity.
Clinical Information
Clinical Pearls
- Methylene blue is the first-line treatment for symptomatic methemoglobinemia.
- It is contraindicated in patients with G6PD deficiency due to the risk of severe hemolytic anemia; alternative treatments (e.g., exchange transfusion, hyperbaric oxygen) should be considered.
- Methylene blue can cause a false low reading on pulse oximetry and interfere with co-oximetry readings for several hours after administration.
- Urine and sometimes skin will turn blue-green after administration; this is a normal and expected side effect.
- Avoid concomitant use with serotonergic drugs due to the risk of serotonin syndrome, which can be life-threatening.
- The maximum cumulative dose should not exceed 7 mg/kg to avoid paradoxical methemoglobinemia and other toxicities.
Alternative Therapies
- For methemoglobinemia in G6PD deficient patients: Ascorbic acid (less effective), exchange transfusion, hyperbaric oxygen.
- For vasoplegic syndrome (off-label use): Norepinephrine, vasopressin, angiotensin II.
Cost & Coverage
Average Cost:
Varies widely per 2ml vial
Generic Available:
Yes
Insurance Coverage:
Tier 3 or Non-preferred Brand/Generic, often requires prior authorization due to specific indications.
General Drug Facts
If your symptoms or health problems do not improve or worsen over time, it is essential to contact your doctor for further evaluation and guidance. To ensure your safety and the safety of others, never share your prescription medications with anyone, and do not take medications that have been prescribed to someone else.
All medications should be stored in a secure location, out of the reach of children and pets, to prevent accidental ingestion. When disposing of unused or expired medications, do not flush them down the toilet or pour them down the drain unless specifically instructed to do so by a healthcare professional or the medication's packaging. Instead, consult with your pharmacist to determine the best disposal method, as some communities have designated drug take-back programs.
Additionally, some medications may have a separate patient information leaflet; check with your pharmacist to see if this applies to your prescription. If you have any questions or concerns about your medication, it is crucial to discuss them with your doctor, nurse, pharmacist, or other healthcare provider.
In the event of a suspected overdose, immediately contact your local poison control center or seek emergency medical attention. Be prepared to provide information about the medication, including the name, dosage, and time it was taken, to ensure prompt and effective treatment.
All medications should be stored in a secure location, out of the reach of children and pets, to prevent accidental ingestion. When disposing of unused or expired medications, do not flush them down the toilet or pour them down the drain unless specifically instructed to do so by a healthcare professional or the medication's packaging. Instead, consult with your pharmacist to determine the best disposal method, as some communities have designated drug take-back programs.
Additionally, some medications may have a separate patient information leaflet; check with your pharmacist to see if this applies to your prescription. If you have any questions or concerns about your medication, it is crucial to discuss them with your doctor, nurse, pharmacist, or other healthcare provider.
In the event of a suspected overdose, immediately contact your local poison control center or seek emergency medical attention. Be prepared to provide information about the medication, including the name, dosage, and time it was taken, to ensure prompt and effective treatment.