Biochemical, Metabolic, and Haematological Alterations in Epileptic Patients on Valproic Acid Therapy: A Cross-Sectional Correlation Study

Background: Valproic acid (VPA) shows wide interindividual variability in serum levels, leading to differences in seizure control and adverse effects. Therapeutic drug monitoring (TDM) may help optimise treatment and guide rational dose adjustment in routine clinical practice. Objective: To estimate serum trough VPA levels and correlate them with clinical response in epileptic patients on monotherapy. Methods: A prospective cross-sectional study was conducted on 100 adult epilepsy patients receiving stable sodium valproate monotherapy. Trough serum levels were measured by HPLC and correlated with seizure control and adverse drug reactions using appropriate statistical methods. Results: Mean serum VPA level was 72.5 ± 23.4 ?g/mL. Complete seizure control was seen in 61% of patients and was associated with higher serum levels. A significant positive correlation was found between serum VPA concentration and seizure control (r = 0.42, p = 0.002), while dose showed no significant correlation. Adverse effects occurred in 19% of patients. Conclusion: Serum VPA levels correlate better with clinical response than prescribed dose. Routine TDM can support individualized therapy, improve seizure outcomes, enhance patient safety, and reduce the risk of toxicity in epilepsy management.