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Free Valproic Acid: Steady-State Pharmacokinetics in Patients with Intractable Epilepsy

Published online by Cambridge University Press:  18 September 2015

N. Otten ,
K. Hall ,
J. Irvine-Meek ,
M. Leroux ,
D. Budnik  and
S. Seshia
N. Otten*
Affiliation:
the Departments of Pharmaceutical Services, (Drs. Otten, Hall, and Irvine-Meek), Clinical Chemistry, (Mr. Leroux and Ms. Budnik). and Pediatrics, (Dr. Seshia), Health Sciences Centre and University of Manitoba
K. Hall
Affiliation:
the Departments of Pharmaceutical Services, (Drs. Otten, Hall, and Irvine-Meek), Clinical Chemistry, (Mr. Leroux and Ms. Budnik). and Pediatrics, (Dr. Seshia), Health Sciences Centre and University of Manitoba
J. Irvine-Meek
Affiliation:
the Departments of Pharmaceutical Services, (Drs. Otten, Hall, and Irvine-Meek), Clinical Chemistry, (Mr. Leroux and Ms. Budnik). and Pediatrics, (Dr. Seshia), Health Sciences Centre and University of Manitoba
M. Leroux
Affiliation:
the Departments of Pharmaceutical Services, (Drs. Otten, Hall, and Irvine-Meek), Clinical Chemistry, (Mr. Leroux and Ms. Budnik). and Pediatrics, (Dr. Seshia), Health Sciences Centre and University of Manitoba
D. Budnik
Affiliation:
the Departments of Pharmaceutical Services, (Drs. Otten, Hall, and Irvine-Meek), Clinical Chemistry, (Mr. Leroux and Ms. Budnik). and Pediatrics, (Dr. Seshia), Health Sciences Centre and University of Manitoba
S. Seshia
Affiliation:
the Departments of Pharmaceutical Services, (Drs. Otten, Hall, and Irvine-Meek), Clinical Chemistry, (Mr. Leroux and Ms. Budnik). and Pediatrics, (Dr. Seshia), Health Sciences Centre and University of Manitoba
*
Department of Pharmaceutical Services, General Hospital, 700 William Avenue, Winnipeg, Manitoba, Canada R3E 0Z3
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Abstract

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Free and total valproic acid (VPA) pharmacokinetic evaluation was carried out at steady state in six young epileptics who were also receiving other anticonvulsants. Subjects received their usual morning dose of VPA after an overnight fast. Blood samples for free and total VPA were taken prior to the dose and frequently thereafter for 12 hours. The calculated pharmacokinetic parameters for total VPA and free VPA were: half-lives of 7.5 ± 1.6 hours and 5.0 ± 1.5 hours, volumes of distribution of 0.189 ± 0.038 l/kg and 1.51 ± 0.98 l/kg, and clearances of 0.30 ± 0.06 and 3.6 ± 2.0 ml/min/kg., respectively. There was a strong correlation between percent free VPA and total VPA (r = 0.81) but marked inter- and intra-subject variations were seen. Studies attempting to correlate VPA levels to clinical response must take such data into account.

Type
Original Articles
Information
Canadian Journal of Neurological Sciences , Volume 11 , Issue 4 , November 1984 , pp. 457 - 460
Copyright
Copyright © Canadian Neurological Sciences Federation 1984

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