Since PM is not active until converted to PMP or PLP (via PMP)R, its diversion to glycation and AGE inhibitions may mean that dosages of PM which create B6 toxicity are greater than of PN. Unfortunately, this has not been experimentally proven or disproven.
J Appl Toxicol. 2004 Nov-Dec;24(6):497-500. Pyridoxine (vitamin B6) neurotoxicity
Nathan S. Kline Institute for Psychiatric Research, Orangeburg, New York 10962, USA.
“The vitamers related to pyridoxine (pyridoxal, pyridoxamine) and the coenzyme (pyridoxal 5-phosphate) did not cause clinical signs or lesions similar to those produced by pyridoxine even when injected in maximum tolerated doses.”
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“Pharmacokinetic assessments were performed after the first (0 to 12 hours) and last (0 to 48 hours) dose of each dosing level. After the first dose of each dosing level, the time of maximum concentration was approximately 2.5 hours. The maximum drug concentration was 1 and 1.5 µg/hr/mL at 250 and 500 mg doses, respectively. Pharmacokinetic parameters observed after multiple dosings were not significantly different than after a single dose, indicating lack of drug accumulation, Dr. Degenhardt said.”
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ADA: Pyridoxamine Appears to be Safe, Well Tolerated for Patients with Diabetic Nephropathy
By Bruce Sylvester
ORLANDO, FL -- June 8, 2004 -- Investigative pyridoxamine (Pyridorin, PYR-206) appears to be both safe and well tolerated as treatment for diabetic nephropathy, say researchers.
Reporting here on June 6 at annual meeting of the American Diabetes Association, Thorsten Degenhardt, PhD, presenter and project director for BioStratum, Durham, North Carolina, stated, "We did not really see any dose toxicity in our study. Pyridoxamine seems to be safe and it was well-tolerated by this patient population."