Abstracts

Rationale: Epilepsy is a disease requiring chronic therapy with AED(s). Many conventional AEDs currently available have either too rapid an absorption or elimination, requiring the patient to take multiple doses per day, which may adversely impact adherence or cause peak-related side effects. Consequently, some AEDs with immediate-release (IR) characteristics have been modified to prolong absorption and/or reduce peak serum concentration, enabling dosage regimen simplification (Pellock, Epilepsy Research 2004; 301-7). Modified-release AED formulations have been labeled with various suffixes or names (XL, XR, CR, ER, SA, -Chrono), but such labeling may not adequately distinguish those modified-release AEDs with the most prolonged absorption or unique formulation characteristics. Such suffixes lack precise definition. We identified the formulation characteristics of currently available modified-release AEDs, attempting to distinguish them by suffix designation.Methods: Six modified-release AEDs formulations, representing 4 different AEDs, were characterized, utilizing information from FDA-approved inserts (2001+) and published literature.Results: The formulation characteristics of available modified-release AEDs are quite variable (table).Conclusions: When all modified-release AEDs are compared, suffix designations do not provide distinguishable information about formulation characteristics. Clarification of modified-release AED suffix terminology may be warranted.