Evaluation of the safety and tolerability of intravenous undiluted levetiracetam at a pediatric institution.

STUDY OBJECTIVE: Recent studies suggest rapid administration of high-dose, undiluted levetiracetam is safe in adults; however, no information exists in pediatric patients. The purpose of this study was to evaluate the safety and tolerability of undiluted levetiracetam at a pediatric institution. DESIGN: Retrospective, single-center, cohort study. SETTING: Pediatric Academic Medical Center. PATIENTS: All patients who received high-dose >60 mg/kg (-10%) up to 4500 mg undiluted or diluted intravenous levetiracetam were included. INTERVENTION: Rapid intravenous administration of undiluted versus diluted levetiracetam. MEASUREMENTS AND MAIN RESULTS: A total of 776 levetiracetam doses were included, 358 doses administered and 418 doses wasted. The doses administered (61 undiluted and 297 diluted) accounted for a total of 252 patients (39 received undiluted, and 213 received diluted levetiracetam) (median [minimum-maximum range] age, 2 years [1 day to 32.7 years]; mean (standard deviation [SD]) weight, 20.1 kg [22.1 kg]). The incidence of hemodynamic disturbances and infusion-related reactions was not statistically significant between undiluted (24.6%) and diluted (26.3%) groups (p = 0.87). The median (interquartile range [IQR]) time difference between first-line antiseizure medication and levetiracetam administration in patients with status epilepticus was 18 min (10.5-30.5) in the undiluted group versus 36.5 min (21.8-67.3) in the diluted group (p < 0.01). Additionally, there was a significant amount of drug waste from dispensed but not administered doses of the diluted bag compared to undiluted vials (57.6% diluted vs. 18.7% undiluted, p < 0.001). CONCLUSION: Undiluted levetiracetam was not associated with an increased incidence of adverse effects compared to diluted levetiracetam in high-doses, up to 4500 mg given over 5 min in pediatric patients.

Native and invasive squirrels show different behavioural responses to scent of a shared native predator.

Invasive species pose a serious threat to native species. In Europe, invasive grey squirrels (Sciurus carolinensis) have replaced native red squirrels (Sciurus vulgaris) in locations across Britain, Ireland and Italy. The European pine marten (Martes martes) can reverse the replacement of red squirrels by grey squirrels, but the underlying mechanism of how pine martens suppress grey squirrels is little understood. Research suggests the reversal process is driven by direct predation, but why the native red squirrel may be less susceptible than the invasive grey squirrel to predation by a commonly shared native predator, is unknown. A behavioural difference may exist with the native sciurid being more effective at avoiding predation by the pine marten with which they have a shared evolutionary history. In mammals, olfactory cues are used by prey species to avoid predators. To test whether anti-predator responses differ between the native red squirrel and the invasive grey squirrel, we exposed both species to scent cues of a shared native predator and quantified the responses of the two squirrel species. Red squirrels responded to pine marten scent by avoiding the feeder, increasing their vigilance and decreasing their feeding activity. By contrast, grey squirrels did not show any anti-predator behaviours in response to the scent of pine marten. Thus, differences in behavioural responses to a shared native predator may assist in explaining differing outcomes of species interactions between native and invasive prey species depending on the presence, abundance and exposure to native predators.