Analysis of variability of concentrations of valproic acid (VPA) and its selected metabolites in the blood serum of patients treated with VPA and patients hospitalized because of VPA poisoning

Aim of the study: To compare the metabolic profile of valproic acid (VPA) in the studied groups of cases through an analysis of variability of concentrations of VPA with its selected metabolites (2-ene-VPA, 4-ene-VPA, 3-keto-VPA).

Study material: Blood serum samples collected from 27 patients treated with VPA drugs in the Psychiatry Unit and in the Neurology and Cerebral Strokes Unit at the Ludwik Rydygier Provincial Specialist Hospital in Krakow, and blood serum samples collected from 26 patients hospitalized because of suspected acute VPA poisoning at the Toxicology Department, Chair of Toxicology and Environmental Diseases, Jagiellonian University Medical College in Krakow.

Results and conclusions: The analysis of concentrations of VPA and its selected metabolites has shown that the metabolic profile of VPA determined in cases of acute poisoning is different from cases of VPA therapy. One of VPA’s metabolic pathways – the process of desaturation – is unchanged in acute poisoning and prevails over the process of -oxidation. The ingestion of toxic VPA doses results in an increased formation of 4-ene-VPA, proportional to an increase in VPA concentration. Acute VPA poisoning involves the saturation of VPA’s metabolic transformations at the stage of -oxidation. The process of oxidation of 2-ene-VPA to 3-keto-VPA is slowed down after the ingestion of toxic doses.