Levetiracetam Rectal Administration in Healthy Dogs

BACKGROUND Levetiracetam is used to manage status epilepticus (SE) and cluster seizures (CS) in humans. The drug might be absorbed after rectal administration and could offer a practical adjunct to rectal administration of diazepam in managing SE and CS. HYPOTHESIS Levetiracetam is rapidly absorbed after rectal administration in dogs and maintains target serum concentrations for at least 9 hours. ANIMALS Six healthy privately owned dogs between 2 and 6 years of age and weighing 10-20 kg. METHODS Levetiracetam (40 mg/kg) was administered rectally and blood samples were obtained immediately before (time zero) and at 10, 20, 40, 60, 90, 180, 360, and 540 minutes after drug administration. Dogs were observed for signs of adverse effects over a 24-hour period after drug administration. RESULTS CLEV at 10 minutes was 15.3 ± 5.5 μg/mL (mean, SD) with concentrations in the target range (5-40 μg/mL) for all dogs throughout the sampling period. Cmax (36.0 ± 10.7 μg/mL) and Tmax (103 ± 31 minutes) values were calculated and 2 disparate groups were appreciated. Dogs with feces in the rectum at the time of drug administration had lower mean Cmax values (26.7 ± 3.4 μg/mL) compared with those without (45.2 ± 4.4 μg/mL). Mild sedation was observed between 60 and 90 minutes without other adverse effects noted. CONCLUSIONS AND CLINICAL IMPORTANCE This study supports the use of rectally administered levetiracetam in future studies of clinical effectiveness in the management of epileptic dogs.