Equine Health Update EHU Vol 20 Issue 01 - Page 18

EQUINE | Abstracts Levetiracetam Pharmacokinetics in Foals Pharmacokinetics of the anticonvulsant levetiracetam in neonatal foals K. D. MacDonald, K. A. Hart, J. L. Davis, L. J. Berghaus and S. Giguère Background Results Objective Main limitations Seizures are a common manifestation of neurological disease in the neonatal foal and are an important cause of morbidity and mortality in this population. Current antiepileptic options are effective, but often have un- desirable adverse effects, short duration of action and high cost. Levetiracetam has an ideal safety and phar- macokinetic profile in multiple species, including the adult horse, and may be a safe and cost‐effective al- ternative anticonvulsant in neonatal foals. Due to dif- ferences in drug disposition and clearance dosages in neonates, dosing recommendations in other species or adult horses cannot be extrapolated to foals. To establish the pharmacokinetic profile of single‐dose i.v. and intragastric administration of levetiracetam in healthy neonatal foals. Study design Randomised crossover experimental study. Methods Levetiracetam was administered as a single dose to six healthy foals (ages 1–10 days) at a dose of 32 mg/kg bwt i.v. or intragastrically. Plasma levetiracetam con- centrations were measured using a validated HPLC protocol. 18 After i.v. administration to healthy foals, levetirace- tam had a mean (±s.d.) elimination half‐life of 7.76 ± 0.51 h, a mean systemic clearance of 61.67 ± 10.96 (mL/h/kg) and a mean apparent volume of distribu- tion at steady state of 0.670 ± 0.124 (L/kg). Follow- ing intragastric administration, levetiracetam had a peak concentration of 38.34 ± 7.42 mg/L and time to achieve peak concentration was 0.875 (0.5–1.5) h. Mean bioavailability for IG administration was excel- lent (103.04 ± 14.51%). No significant differences in pharmacokinetic variables between routes and order of administration were observed. Small sample size and single‐dose administration. Conclusions Levetiracetam has excellent intragastric bioavailability in foals and is predicted to maintain plasma concen- trations at or above the proposed target concentration with twice daily i.v. or oral administration. Once‐daily administration may be possible in some foals based on the therapeutic range recommended in other species. http://onlinelibrary.wiley.com/doi/10.1111/evj.12790/full • Equine Health Update •