Effect of vitamin C on plasma total antioxidant status in patients with paraquat intoxication.
This study was conducted to evaluate whether vitamin C (VC) was associated with total antioxidant status (TAS) in human plasma and to determine the usefulness of VC on TAS in the treatment of patients with paraquat poisoning. VC and TAS were measured in 56 healthy subjects. Then, various concentrations (1-100 mg/dl) of VC in pooled plasma from 10 volunteers were constructed in vitro and TAS was measured. The VC and TAS were measured in vivo at 0.5, 1, 2, 3, 5, 7, 9, and 11 h after injection of VC (50 mg/kg) in seven volunteers and pharmacokinetic data were calculated. Finally, various amounts of VC (100, 500, 1000, 3000 mg/day, and 3000 mg/8 h) were given to 10 paraquat-poisoned patients for 5 consecutive days, and blood was taken for TAS 1 h after each injection. The means (SD) of VC and TAS in healthy subjects were 2.22 (0.16) mmol/l and 0.48 (0.10) mg/dl, respectively. Positive correlation between VC and TAS was observed in both in vitro and in healthy volunteers. The pharmacokinetic results in vivo were as follows: means (SD) of distribution volume, area under curve, plasma clearance, half life, C(max), and T(max) were 32.0 (4.4) l, 36.4 (11.3) mg h/dl, 2.13 (1.36) l/h, 10.2 (7.8) h, 17.1 (7.1) mg/dl, and 0.64 (0.24) h, respectively. Estimated loading and maintenance doses of VC were 2278 mg and 146 mg/h, respectively. The means of TAS were increased over 5 consecutive days as 2.26, 2.76, 2.81, 3.18, and 3.58 mmol/l in paraquat patients. All patients were recovered within mean (SD) 21.2 (5.4) admission days. Our data suggested that VC was a significant antioxidant as TAS in human plasma and that increased TAS by high doses of VC could be useful as a free radical scavenger for paraquat poisoned patients.
Hong
Sae Yong
SY
Institute of Pesticide Poisoning, Soonchunhyang University Chunan Hospital, 23-20 Bongmyung-Dong, Chungnam 330-100, Chunan City, Republic of Korea.
Hwang
Kyu Yoon
KY
Lee
Eun Young
EY
Eun
Soo Whon
SW
Cho
Suk Ran
SR
Han
Chan Soo
CS
Park
Yung Hyun
YH
Chang
Sung Keun
SK
D000328:Adult; D000975:Antioxidants / Q000378:metabolism* / Q000493:pharmacokinetics / Q000494:pharmacology*; D001205:Ascorbic Acid / Q000378:metabolism / Q000493:pharmacokinetics / Q000494:pharmacology*; D001772:Blood Cell Count; D001794:Blood Pressure / Q000187:drug effects; D001831:Body Temperature / Q000187:drug effects; D005260:Female; D016166:Free Radical Scavengers / Q000378:metabolism / Q000493:pharmacokinetics / Q000494:pharmacology; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D007677:Kidney Function Tests; D008111:Liver Function Tests; D008297:Male; D008875:Middle Aged; D010269:Paraquat / Q000506:poisoning*; D011041:Poisoning / Q000097:blood / Q000188:drug therapy
D000975:Antioxidants; D016166:Free Radical Scavengers; D010269:Paraquat; D001205:Ascorbic Acid