1043-3155 Pediatr Neurol Briefs pedneurbriefs Pediatr Neurol Briefs Pediatric Neurology Briefs Pediatr Neurol Briefs 2166-6482 1043-3155 2166-3155 Pediatric Neurology Briefs Publishers Chicago, IL, USA PNB-6-70-a 10.15844/pedneurbriefs-6-9-8 Antiepileptic Drugs Neurology Pediatrics Nervous System Diseases Child Development Brain Diseases Neurosurgery Child Infant Phenytoin and Folic Acid http://orcid.org/0000-0002-0173-7931 Millichap J. Gordon MD 1 2 * Division of Neurology, Children's Memorial Hospital, Chicago, IL Departments of Pediatrics and Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL Correspondence: Dr. J. Gordon Millichap, E-mail: jgmillichap@northwestern.edu 09 1992 01 07 2016 6 9 70 70 Copyright: © 1992 The Author(s) 1992 This work is licensed under the Creative Commons Attribution 4.0 International License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Phenytoin pharmacokinetics: before and after folic acid administration

The pharmacokinetics of phenytoin (PHT) before and after administration of 1 and 5 mg of folic acid is reported from the Colleges of Pharmacy and Medicine, University of Iowa, Iowa City and University of Health Sciences/The Chicago Medical School, Chicago, IL.

 Phenytoin Folic Acid Metabolism

The pharmacokinetics of phenytoin (PHT) before and after administration of 1 and 5 mg of folic acid is reported from the Colleges of Pharmacy and Medicine, University of Iowa, Iowa City and University of Health Sciences/The Chicago Medical School, Chicago, IL. The measured total serum PHT concentration was always greater than the calculated concentration and the days to the steady state concentration were always longer than the number calculated before folic acid was given. All subjects showed decreased serum folic acid following PHT. Since folate is assumed to be a co-factor in PHT metabolism, these results were expected because depletion of the vitamin would result in reduced metabolism of PHT and higher total serum PHT and longer time to reach steady state. When folic acid was added the same results were obtained. The depletion of folic acid had to be corrected first before its role as a co-factor in PHT metabolism could be used. [1]

COMMENT. The authors suggest that folic acid should be prescribed when phenytoin therapy is initiated.

 Berg MJ Fincham RW Ebert BE Schottelius DD Phenytoin pharmacokinetics: before and after folic acid administration Epilepsia 1992 Jul-Aug 33 4 712 720 10.1111/j.1528-1157.1992.tb02352.x 1628589