Abstracts

Rationale: Intravenous (IV) fosphenytoin (FOS) and levetiracetam (LEV) are commonly used for urgent seizure control and prophylaxis of seizures in patients presenting with acute cerebral disorders including cerebrovascular accidents (ischemic and hemorrhagic), seizures and traumatic brain injuries. Hypotension has been reported but occurs rarely after IV infusion of FOS and LEV in the general population. The exact incidence and extent of hypotension after infusion of FOS and LEV in patients presenting with acute cerebral insults is not known but is essential to determine in this subgroup of patients because it may impact negatively on the clinical outcome. Methods: We retrospectively collected data for all consecutive patients who received IV infusions of a single dose of 750 mg or higher of either FOS or LEV at our medical institution over the last 12 months. We included all patients that have documented blood pressure readings within 2 hours before and 2 hours after the IV infusion. We excluded all patients who concurrently received medications (hypertension medications, vasopressors, and all sedatives) that may affect blood pressure in the 2 hours before, during or the 2 hours after the end of infusion. We compared blood pressure values immediately before the infusion with the lowest values obtained within 2 hours after infusion. Results: 148 charts were reviewed (78 patients received FOS and 71 received LEV) to include 50 patients that satisfied the inclusion and exclusion criteria in each group (see table 1 for summary of the demographics and clinical presentations). Most patients (76% of the FOS group and 84% of the LEV group) received 1000 mg of IV infusion; the mean infusion rate was 39 and 41 mg per minute in the FOS and LEV groups respectively. The mean time of blood pressure collection was 31 and 32 minutes before the infusion and 62 and 64 minutes after infusion in the FOS and LEV groups respectively. Statistically significant (p < 0.001) drop in the systolic, diastolic and mean blood pressures (MBP) were found in the FOS group after infusion. The average decrease in the MBP was 11 mm Hg. 88% of patients who received FOS had decrease in their MBP readings after the infusion (62% had > 10 mm Hg decrease in their MBP). None of these BP parameters were significantly changed in the LEV group. Only 2 of the 50 patients (4%) in the LEV group had > 10 mm Hg decrease in their MBP. Conclusions: IV FOS infusion in patients presenting with acute cerebral insults may cause significant decreases in blood pressure. This is concerning especially when maintaining optimal MBP is critical in the management of these patients. IV LEV infusion did not cause significant changes in the MBP in the same patient population.