Successful use of intravenous and oral levetiracetam in a goat to control refractory seizures secondary to suspected polioencephalomalacia.

ABSTRACT

OBJECTIVE: To assess the clinical efficacy and plasma concentrations of levetiracetam in a goat with seizures. ANIMAL A 5-month-old doeling. CLINICAL PRESENTATION, PROGRESSION, AND PROCEDURES The goat was referred because of progressive anorexia and lethargy over 3 days. Clinical signs consisted of weakness, obtundation, opisthotonos, anisocoria, and cortical blindness. Initial evaluation was most consistent with polioencephalomalacia. TREATMENT AND OUTCOME: Neurologic improvement occurred within 4 hours of thiamine administration, with appetite returning over 12 hours. On day 3 of hospitalization, the goat suffered acute onset repetitive seizures that were incompletely responsive to standard interventions over 3 hours. Administration of IV levetiracetam (60 mg/kg) produced resolution of seizure activity within 20 minutes. Levetiracetam was continued twice daily IV, then PO after day 6. Plasma concentrations were above or within therapeutic ranges (5 to 45 µg/mL) as previously established for other species, following both IV and PO levetiracetam. Oral administration (60 mg/kg, PO, q 12 h) resulted in plasma levetiracetam concentrations of 48.1 µg/mL 2 hours after a dose and 23.4 µg/mL 2 hours prior to the next dose. CLINICAL RELEVANCE Levetiracetam is a newer anticonvulsant commonly used in humans and small animals due to its efficacy, cost, and wide safety margin. Its use has not previously been reported in domestic small ruminants. In this case, levetiracetam showed excellent clinical efficacy in the face of refractory seizures, with no apparent side effects. Plasma concentrations during oral administration were at the high end of the therapeutic range, indicating absorption in a nonmonogastric species. Further studies are warranted to determine optimal dosing in small ruminants.