“Administration of pyridoxine·HCl (200 mg/kg/day for 3 days) in addition to carbidopa blocked the fall in hypothalamic AAAD activity.”
“However, the coadministration of pyridoxine with carbidopa can maintain tissue PLP levels and protect against such enzyme changes.”
“Repeated administration of carbidopa (three 100 mg/kg doses per day for 3 days) lowered PLP concentrations in serum, liver, and muscle (by 88%, 51%, and 18%, respectively) among rats killed 2 hr after the final injection.”
“These findings suggest that large doses of carbidopa can, by depleting tissues of PLP , cause potentially undesirable nonspecific changes in pyridoxine-dependent enzymes.”