Pharmacokinetic and Safety Trial of Intravenous Levetiracetam in the Treatment of Neonatal Seizures

In adults, drug clearance is less than half of the glomerular filtration rate and the drug half-life is 6-8 hours. Renal function in infants at birth is characterized by immature glomerular filtration and is only 20% that of older children. The specific esterase responsible for levetiracetam hydrolysis has not been identified and its expression in newborn infants is unknown. Depending on its activity, the expected infant total levetiracetam clearance will likely be between 15-45% of older populations. However, due to immaturity in levetiracetam clearance in infants, accumulation with multiple dosing is possible. Therefore the maintenance dose is reduced compared to older children according to the anticipated impaired clearance. These anticipated differences in levetiracetam clearance and volume of distribution, will likely result in a prolonged drug half-life of 10-30 hours in infants. This prolonged elimination will require longer sampling to adequately characterize levetiracetam pharmacodynamics in this population. The primary intent of the data analysis is to determine levetiracetam pharmacokinetics in newborn infants and predict the dosage necessary to maintain concentrations similar to those seen with effective therapy in other populations. Graphs of serum concentration vs. time will be plotted for levetiracetam for each infant. Mean serum drug concentration vs. time curves will also be constructed. Summary statistics (i.e., n, mean, standard deviation, minimum, maximum, and coefficient of variation) will be calculated for serum concentrations for each time point and each dose level.