2017 ACVIM Forum Research Abstract Program

there are no studies evaluating its disposition in dogs with epilepsy. The objective of this study was to evaluate the pharmacokinetics of LEV-XR in epileptic dogs when administered alone, or concurrently with other AEDs. A population pharmacokinetic approach and non-linear mixed effects modeling (NLME) was used to examine the variation and source of variation in our population. Eighteen client-owned dogs on maintenance therapy with LEV-XR only (Group L, n = 6), LEV-XR and phenobarbital (Group LP, n = 6) or LEV-XR and zonisamide (Group LZ, n = 6) were enrolled. All drugs were examined at steady state concentrations. Blood samples were collected at 0, 2, 4, 8 and 12 hours after the morning dose of LEV-XR was administered with food. The LP group had significantly lower C MAX compared to the L and LZ groups (13.48 AE 9.48 vs. 33.93 AE 29.84 and 34.13 AE 9.01 lg/ mL, respectively), significantly lower AUC (134.15 AE 153.67 vs. 353.10 AE 284.11 and 452.80 AE 116.89 h•lg/mL, respectively), and significantly higher CL/F (0.17 AE 0.20 vs. 0.08 AE 0.07 and 0.07 AE 0.02 L/kg/hours, respectively), demonstrating that concurrent administration of phenobarbital significantly lowers the LEV concentration in epileptic dogs. Elimination half-life was similar among groups (L, 1.46 AE 2.08 hours; LP, 1.54 AE 1.97 hours; LZ, 1.57 AE 1.13 hours), but shorter than previously reported in healthy dogs. These findings warrant consideration when utilizing LEV-XR as a treatment for epilepsy in dogs. The most frequently occurring non-infectious inflammatory lesion of the canine spine is steroid-responsive meningitis-arteritis (SRMA), while pure myelitis is a rare disease in dogs. Although meningomyelitis of unknown cause and granulomatous meningomyelitis are the most common diagnoses in canine cases, non-infectious myelitis responsive to glucocorticoid treatment has not been well described. This report describes the clinical and diagnostic features of steroid-responsive myelitis (SRM), which were different to those of SRMA, in five dogs.