Methylene blue can cause serotonin syndrome, which can be serious or fatal, when taken with serotonergic medicines. These include antidepressants (SSRIs, SNRIs and MAO inhibitors), opioids, linezolid and dextromethorphan. The injectable form carries an FDA boxed warning for this. Tell your care team every medication and supplement you take.
Methylene blue is FDA approved as an intravenous treatment for methemoglobinemia, a blood disorder. Using it for focus, energy or aging is off-label, which means the FDA has not reviewed it for those uses.
Tell your care team straight away if you get agitation, confusion, shivering, muscle twitching or fever, especially if you take an antidepressant. Also tell us if your urine goes dark or your skin yellows, you feel unusually weak or look pale, you have a seizure, or you get a severe rash or trouble breathing.
Common side effects
- headache
- low potassium
- diarrhea
- low magnesium
- muscle jerking
- nausea
Rare but serious
- serotonin syndrome
- breakdown of red blood cells, which can be delayed
- serious harm if you have G6PD deficiency
- harm to a pregnancy
- falsely low oxygen readings on a finger monitor
Do not take this if you have G6PD deficiency, or you have reacted badly to methylene blue or thiazine dyes before.
This is not a complete list of side effects. Message your care team about any symptom that worries you. What we dispense is a compounded preparation made by a licensed US pharmacy. Compounded medications are not approved by the FDA for safety, efficacy or quality.
