Effectiveness of therapeutic drug monitoring of phenytoin and valproic acid in children in a hospital setting / Noor Isah Taip

The study was conducted to predict the effectiveness of phenytoin and valproic acid Therapeutic Drug Monitoring (TOM) in children in a hospital setting. The data of patients were collected from Hospital Sultanah Aminah, Johor Bharu (HSAJB) and consisted of 88 patients at which 57 patients are male and 31 patients are female. Patients' demographics and pharmacokinetic data were evaluated to observe the correlation between parameters. The evaluation has shown that there is a strong relationship between the drug level of phenytoin and its clearance with R2 value of 0.5629 while valproic acid shown moderate relationship with R2 value of 0.4474. Clearance of both phenytoin and valproic acid were also analysed against dose per kg and dose per day. The mean of clearance of phenytoin in this study is (0.49 ± 0.31 L/kg/hr) while the mean of clearance of valproic acid is ( 14.35 ± 7.75 ml/kg/hr). The pharmacokinetic of patients in terms of the coefficient of variance (COY) has shown high inter­ patient variability for value of more than I 0%. The pattern and trend of pharmacokinetic parameters in children treated with phenytoin and valproic acid is also identified. There is no significant difference of pharmacokinetic parameters between gender and race. The most affected parameter is clearance and it is relevant to monitor both drugs to ensure the therapeutic effectiveness can be optimized.