{"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":11857,"journal":{"name":"European Journal of Clinical Pharmacology","volume":" ","pages":"1751-1759"},"PeriodicalIF":2.4000,"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":"European Journal of Clinical Pharmacology","FirstCategoryId":"3","ListUrlMain":"https://doi.org/10.1007/s00228-024-03741-2","RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"2024/8/16 0:00:00","PubModel":"Epub","JCR":"Q3","JCRName":"PHARMACOLOGY & PHARMACY","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.
期刊介绍:
The European Journal of Clinical Pharmacology publishes original papers on all aspects of clinical pharmacology and drug therapy in humans. Manuscripts are welcomed on the following topics: therapeutic trials, pharmacokinetics/pharmacodynamics, pharmacogenetics, drug metabolism, adverse drug reactions, drug interactions, all aspects of drug development, development relating to teaching in clinical pharmacology, pharmacoepidemiology, and matters relating to the rational prescribing and safe use of drugs. Methodological contributions relevant to these topics are also welcomed.
Data from animal experiments are accepted only in the context of original data in man reported in the same paper. EJCP will only consider manuscripts describing the frequency of allelic variants in different populations if this information is linked to functional data or new interesting variants. Highly relevant differences in frequency with a major impact in drug therapy for the respective population may be submitted as a letter to the editor.
Straightforward phase I pharmacokinetic or pharmacodynamic studies as parts of new drug development will only be considered for publication if the paper involves
-a compound that is interesting and new in some basic or fundamental way, or
-methods that are original in some basic sense, or
-a highly unexpected outcome, or
-conclusions that are scientifically novel in some basic or fundamental sense.