Methylene Blue

pharmacological · nervous · Oral · IV

Methylene Blue. Phenothiazine dye — at low doses (0.5–4 mg/kg) acts as a mitochondrial alternate electron carrier (cytochrome c shunt) + MAO-A… Oral half-life 5.3 h.

Phenothiazine dye — at low doses (0.5–4 mg/kg) acts as a mitochondrial alternate electron carrier (cytochrome c shunt) + MAO-A inhibitor. Used clinically for methemoglobinemia + ifosfamide encephalopathy. Biohacker interest in low-dose for cognition + mitochondrial support; serotonin syndrome risk with SSRIs at higher doses.

PK: F 0.7 IS REFUTED BY ITS OWN CITED ABSTRACT. That study dosed 100 mg by both routes and reports "the area under the concentration-time curve was much lower (9 nmol/min/ml vs 137 nmol/min/ml)", which is a bioavailability near 0.066 — an order of magnitude below the stored value, computable from the paper own two numbers. That ratio is now stored and flagged as derived rather than quoted, because deleting it would leave the resolver default overstating oral exposure more than tenfold. No better figure exists: the literature is self-contradictory, giving 6.6% for immediate release against a stated "F(abs)=139.19 +/- 52.00%" for a delayed-release tablet, and a bioavailability of 139% is physically impossible. The half-life of 5.25 h is verbatim but is a WHOLE-BLOOD, multiphasic, explicitly "estimated" value for the intravenous route; the oral terminal slope is absorption-limited at 6-27 h. V 250 L is dropped as a MATRIX ARTEFACT — the reference matrix is whole blood and the drug partitions heavily into tissue. ka 0.15 is the wrong model, not merely uncited: the oral product is delayed-release with a median time to peak of 12-16 h and saturable, food-dependent absorption.

Pharmacokinetics