Incidence of Postoperative Seizures with and without Levetiracetam Pretreatment in Dogs Undergoing Portosystemic Shunt Attenuation

Background: In dogs with congenital portosystemic shunts (CPS), postligation seizures can be challenging to treat and often result in mortality. Levetiracetam (LEV) is a novel anticonvulsive drug that is commonly used in humans with seizure disorders who have hepatic comorbidity. Objectives: To compare the incidence of postoperative seizures in dogs that underwent surgical attenuation of an extrahepatic CPS and preoperatively received either LEV or no anticonvulsant medication. Animals: A total of 126 dogs undergoing attenuation of an extrahepatic CPS that preoperatively received either LEV or no anticonvulsant medication. Methods: Retrospective case review. Information obtained included signalment, duration of clinical signs, presence of neurologic abnormalities before surgery, preoperative bile acid and ammonia concentrations, diagnostic imaging modality, duration of hospitalization, postoperative complications including seizures, and discharge status. Bayesian Poisson regression was used to estimate the risk of seizures in LEV-treated dogs when compared with untreated dogs. Results: Levetiracetam was administered to 33% (42/126) of dogs. No dog treated with LEV experienced postoperative seizures, whereas 5% (4/84) of dogs not treated with LEV experienced postoperative seizures. The relative risk of seizures was significantly (P <.0002) < 1 for the LEV-treated dogs, indicating LEV protection against development of postoperative seizures. No dog that experienced postoperative seizures survived to discharge from the hospital. Conclusions and Clinical Importance: Levetiracetam administered at 20 mg/kg PO q8h for a minimum of 24 hours before surgery significantly decreased the risk of postoperative seizures and death in dogs undergoing surgical attenuation of extrahepatic CPS with ameroid ring constrictors.