Therapeutic drug monitoring for valproate: deriving a novel formula for calculation of free concentration.

Autor: Pretorius E; Department of Pharmacology, Faculty of Health Sciences, University of the Free State, Bloemfontein, South Africa. pretoriusneurology@gmail.com., van Zyl P; Department of Pharmacology, Faculty of Health Sciences, University of the Free State, Bloemfontein, South Africa., Joubert G; Department of Biostatistics, Faculty of Health Sciences, University of the Free State, Bloemfontein, South Africa.
Jazyk: angličtina
Zdroj: European journal of clinical pharmacology [Eur J Clin Pharmacol] 2024 Nov; Vol. 80 (11), pp. 1751-1759. Date of Electronic Publication: 2024 Aug 16.
DOI: 10.1007/s00228-024-03741-2
Abstrakt: 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.
(© 2024. The Author(s).)
Databáze: MEDLINE
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