Abstracts

Rationale: To determine if the absorption of oral anti-epileptic medications differs between critically ill patients and healthy individuals.Methods: Retrospective analysis of patients seen in the University of Colorado Hospital Neuro-Intensive Care Unit between November 2005 and November 2006. Following administration of intravenous (fos)phenytoin from an outside facility for subarachnoid hemorrhage, patients who exhibited multi-organ comorbidities were initiated on a regimen of 500 mg of levetiracetam (LEV) oral solution, per NGT twice daily. We compared expected peak serum levels (Cmax, drawn between 45-60 minutes following initial administration) from these critically ill patients against expected peak levels based on population pharmacokinetic data reported in healthy volunteers (UCB Inc. Data on File). Results: A total of 8 subarachnoid hemorrhage patients had LEV serum levels drawn within the expected time-period. Six of eight (75%) of the serum concentrations were undetectable. The patients were all female with average age 60 years. The average length of stay in the neuro-intensive care unit was 33 days, 50% with a diagnosed seizure, 25% with diagnosed status epilepticus, and one death. Conclusions: The absorption of LEV oral solution (based on Cmax) in a critically ill population was unreliable. Multiple factors may be contributing to this phenomenon including altered gastric motility from iatrogenic or general systemic causes. The need for a wider variety of intravenous anti-epileptic preparations is clear.