Three-Year Retention Rates of Levetiracetam, Topiramate, and Oxcarbazepine: A Retrospective Hospital-Based Study

Abstract

Objectives: We evaluated and compared the 3-year retention rates of levetiracetam (LEV), topiramate (TPM), and oxcarbazepine (OXC) in patients with epilepsy in routine clinical practice. Methods: We retrospectively reviewed medical records of patients with epilepsy who were newly prescribed LEV, TPM, or OXC from 2006 to 2010. The retention rates were estimated by the Kaplan-Meier analysis, and independent risk factors for drug discontinuation were analyzed by the Cox regression method. Results: A total of 588 patients were included: LEV (n = 345), TPM (n = 190), and OXC (n = 53). Among them, 82% had focal epilepsy, whereas 14.8% had generalized epilepsy. The 3-year retention rates for LEV, TPM, and OXC, were 81.2%, 78.3%, and 54.7%, respectively. Levetiracetam and TPM had equivalent retention rates, whereas patients remained on OXC for a significantly shorter amount of time (P < 0.001). A lower retention rate for OXC was also evident in the subgroup analysis of focal epilepsy (P < 0.001). In generalized epilepsy, LEV and TPM revealed comparable retention rates (P = 0.255). The seizure-freedom rate did not differ among groups, whereas the rate of adverse effects leading to drug withdrawal of OXC (87.5%) was higher than that of LEV (34.4%, P < 0.001) and TPM (52.5%, P = 0.012). Conclusions: The current study suggested that LEV and TPM had comparable retention profiles in the long-term treatment for both focal and generalized epilepsy. Meanwhile, OXC therapy seemed to be relatively less useful because of its poor tolerability.