Abstracts

Rationale: Both clobazam (CLB) and clonazepam (CLN) have been widely used for many years in Europe for a variety of disorders. However, comparisons of the long-term use of these compounds have not been conducted, particularly for children. The Clinical Practice Research Datalink (CPRD) database, a large, longitudinal primary care database, consists of electronic medical records from general practitioners located throughout the United Kingdom (UK). To compare the actual clinical utilization of CLB and CLN, CPRD data were evaluated for patients <18 years of age receiving CLB vs. CLN for epilepsy. Methods: Patients with ≥1 incident prescription of CLB or CLN within the study period (1995-2011) were included. Date of a patient's first prescription was termed index date. Patients must have also had ≥182 days in the database before index date without any prescriptions of CLB or CLN, to ensure that no previous CLB or CLN had been prescribed. We then evaluated results for the subgroups of children who had a diagnosis of epilepsy any time prior to or ≤90 days after index date. Results: A total of 21,099 patients met inclusion criteria. Of these, 3,882 received CLB, and 17,217 received CLN. CLB use has been predominantly in epilepsy (76.1%), while CLN use in epilepsy was 8.7%. The population of interest (patients <18 years of age) included 574 patients with epilepsy <18 years of age who had received CLB, and 171 patients with epilepsy <18 who had received CLN (table). Greater percentages of children with epilepsy in the CPRD database treated with CLB vs. CLN were receiving concomitant AEDs and comparable percentages were BZD-naïve at baseline. CLN patients had a statistically greater follow-up period compared with CLB patients (6.3 vs. 5.5 years). Median CLB dosage did not increase from baseline to last follow up, while median CLN dosage increased 50%. Conclusions: Greater percentages of children with epilepsy in the CPRD database treated with CLB were receiving concomitant AEDs, consistent with CLB's greater percentage usage for epilepsy vs. CLN. These results also suggest a 10 to 15:1 ratio of CLB dosage to CLN dosage for children with epilepsy. CLB dosage appeared to remain stable over time, while CLN dosage appeared to increase notably from baseline to last follow up, possibly a result of pharmaco-tolerance from long-term use of CLN.