Possible Interaction: Phenobarbital and Vitamin C

“The increases of the hepatic concentration of ascorbic acid and the urinary excretion of ascorbic acid by the treatment with 3MC or PB were markedly suppressed in both EHBRs compared with those in the control SD rats.”

“The intraperitoneal injection with PB (100 mg/day/kg body weight, once a day for 2 days) or MC (20 mg/day/kg body weight, once) significantly elevated the hepatic level of AsA and the urinary excretion of AsA in rats (5-week-old males).”

“Thus it is clear that the treatment with PB or MC stimulates the biosynthesis of AsA by increasing the activity of some enzyme(s) participating in the synthesis prior to GLO.”

“Treatment with phenobarbital , however, also enhances to some extent the biosynthesis of L-ascorbic acid.”

“Despite fasting, the excretion into the urine of d -glucaric and l -ascorbic acid was enhanced after treatment with phenobarbital , and d -glucaric acid reached the levels found in normally fed rats.”

“It is well known that the administration of chloretone, phenobarbital or methylcholanthrene induces an increase in the urinary excretion of ascorbic acid and they also induce an increase in the activities of drug-metabolizing enzyme of liver microsomes (1-3).”

“The stimulatory actions of stress on microsomal metabolism and ascorbic acid levels are additive with those produced by phenobarbital.”

“With all reagents kits, there was no interference from uric acid up to 200 mg/liter, hemoglobin up to 1.0 g/liter, or drugs (clofibrate, phenobarbital , Ketochol, Ovral-28), but negative interferences from ascorbic acid.”

“PREVIOUS studies …, phenobarbital … L-ascorbic acid from glucose through the glucuronic acid pathway1–3 as follows: Evidence for this has come from the observations that these drugs markedly … they stimulate the conversion of glucose-1-14C to labelled D-glucuronic acid, L-gulonic acid and L-ascorbic acid3–5.”