{"title":"Therapeutic drug monitoring for valproate: deriving a novel formula for calculation of free concentration.","authors":"Erna Pretorius, Paulina van Zyl, Gina Joubert","doi":"10.1007/s00228-024-03741-2","DOIUrl":null,"url":null,"abstract":"<p><strong>Background: </strong>Monitoring free valproate concentrations, as with other highly protein-bound anticonvulsants, is essential in clinical situations where protein binding may be disrupted. Conversion of measured total concentrations to approximate free concentrations offers a cost-effective alternative. This study evaluated the relationship between total and free valproate concentrations for discordance and the impact of key determinants. A novel formula was devised that incorporates significant variables.</p><p><strong>Methods: </strong>A multicentre, cross-sectional observational analytical study included 101 subjects 18 years and older using valproate for 6 months or longer. Participants were recruited from private and public sector healthcare settings from primary to tertiary level in, South Africa, during 2017-2019.</p><p><strong>Results: </strong>Free valproate concentrations could be measured for 84 subjects. Discordance for concomitant total and free valproate concentrations was 79.1%. Among 19 participants with elevated free concentrations, 15 (78.9%) had total valproate concentrations within the recommended reference range. Calculations based on the study-derived formula were more accurate in predicting free valproate concentration than previously proposed methods.</p><p><strong>Conclusion: </strong>This study proposes that the novel formula for calculating free valproate enables more accurate prediction.</p>","PeriodicalId":2,"journal":{"name":"ACS Applied Bio Materials","volume":null,"pages":null},"PeriodicalIF":4.6000,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11458675/pdf/","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"ACS Applied Bio Materials","FirstCategoryId":"3","ListUrlMain":"https://doi.org/10.1007/s00228-024-03741-2","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"2024/8/16 0:00:00","PubModel":"Epub","JCR":"Q2","JCRName":"MATERIALS SCIENCE, BIOMATERIALS","Score":null,"Total":0}
引用次数: 0
Abstract
Background: Monitoring free valproate concentrations, as with other highly protein-bound anticonvulsants, is essential in clinical situations where protein binding may be disrupted. Conversion of measured total concentrations to approximate free concentrations offers a cost-effective alternative. This study evaluated the relationship between total and free valproate concentrations for discordance and the impact of key determinants. A novel formula was devised that incorporates significant variables.
Methods: A multicentre, cross-sectional observational analytical study included 101 subjects 18 years and older using valproate for 6 months or longer. Participants were recruited from private and public sector healthcare settings from primary to tertiary level in, South Africa, during 2017-2019.
Results: Free valproate concentrations could be measured for 84 subjects. Discordance for concomitant total and free valproate concentrations was 79.1%. Among 19 participants with elevated free concentrations, 15 (78.9%) had total valproate concentrations within the recommended reference range. Calculations based on the study-derived formula were more accurate in predicting free valproate concentration than previously proposed methods.
Conclusion: This study proposes that the novel formula for calculating free valproate enables more accurate prediction.