Efficacy and Safety of Valproic Acid Transition Regimens from Intravenous to Oral Administration in Epileptic Patients: A Single-Center Cross-Sectional Study

<b>Objectives</b>: This study aims to evaluate the efficacy and safety of valproic acid (VPA) transition regimens (from intravenous to oral tablets) for anti-seizure treatment. <b>Methods</b>: A retrospective analysis was conducted on inpatients treated with intravenous VPA and oral tablets for epilepsy at the Sir Run Run Shaw Hospital, affiliated with Zhejiang University, between January 2022 and December 2023. Various transition strategies from VPA injections to tablets were examined, and the efficacy and safety of different transition strategies were analyzed. <b>Results</b>: A total of 164 inpatients receiving VPA transition therapy were included in this study, which was divided into three groups based on the transition timing: the 0 h group, the 0-48 h group, and the >48 h group. Regarding VPA dosage, the median daily dose of intravenous VPA was separately 1076.50 mg/day, 1200 mg/day and 1438 mg/day in the 0 h group, 0-48 h group, and the >48 h group. During transition, the daily doses of VPA were significantly higher than that before and after the transition. After completely switching to oral administration, they were all decreased to 1000 mg/day. Moreover, a significant difference regarding the clinical efficacy was observed among the three groups. The >48 h group showed the highest rate of clinical efficacy, which was significantly greater than that of the 0 h group and 0-48 h group. Although there was no statistical significance detected regarding the average blood serum concentrations among the three groups; notably, a higher proportion of patients in the >48 h group (19.35%) had blood concentrations exceeding the desired therapeutic window compared with the 0-48 h group (8.06%) and 0 h group (0%). Adverse events included 30 cases in the 0 h group, 42 in the 0-48 h group, and 67 in the >48 h group, with statistically significant differences in hemoglobin reduction, headache/dizziness, and liver injury. No significant differences were found in digestive and skin-related reactions. <b>Conclusions</b>: The results suggest that the >48 h transition regimen may show some advantages in efficacy but also increases the risk of adverse reactions significantly. Therefore, it is recommended to complete the intravenous-to-oral switch carefully with blood drug concentrations strictly monitored.