A retrospective study on the usage of antiepileptic drugs in Asian children from 2000 to 2009 in the largest pediatric hospital in Singapore

Abstract

In light of the increasing usage of the newer antiepileptic drugs (AEDs) in other countries, we reviewed the prescribing pattern of AEDs in Singapore over the last 10 years (2000-2009). A retrospective review of pharmacy dispensing records solicited from the only children's hospital in Singapore was performed to analyze the trend in AEDs prescribing in the last 10 years. We also examined the correlation between the serum concentrations of valproic acid (VPA), the most-prescribed AED, and seizure control. Descriptive and inferential statistical analyses were then performed on the findings. A total of 41 671 prescriptions on AEDs were retrieved and analyzed. Despite the introduction of the second-generation AEDs, the first generation AEDs still dominate epilepsy treatment in Asian children, with VPA being the mostly prescribed AED (about 40% of the total AEDs usage). The majority of patients (62.8%) were on monotherapy. The mean VPA serum concentration in patients with good seizure control was 68.6 µg/ml (SD = 26.4 µg/ml; range = 12.2-138.0 µg/ml), which was statistically higher than the mean VPA concentration of 57.7 µg/ml (SD = 27.1 µg/ml; range = 11.1-149.0 µg/ml) in patients with poor seizure control (p < 0.0001). With VPA being the most prescribed AED in our clinical practice, and the finding in this study that with careful classification of the patients' condition, serum concentrations of VPA generally correlate well with the seizure control, the correct dose titration of VPA with therapeutic drug monitoring is still of paramount importance.