Flumazenil Treatment for Diazepam-Associated Neurological Signs in a Cat With a Portosystemic Shunt

A 7-month-old female spayed domestic short hair cat was presented for evaluation of inadequate clinical response to medical management for hepatic encephalopathy (HE). An abdominal computed tomography (CT) was to be performed but the cat developed 2 grand mal seizures shortly after presentation. Minimal handling and no drugs had been administered before the seizures. A single dose of diazepam (0.3 mg/kg, IV) was administered after each seizure. Another seizure occurred 24 hours after hospitalization and diazepam (0.5 mg/kg, IV) was once again administered. Seizures ceased but neurological signs worsened and included head pressing, loss of menace response, and a stuporous mentation. Due to unresponsiveness to treatment that included administration of intravenous fluids, levetiracetam, ampicillin/sulbactam, and retention enemas (water with lactulose), a dose of flumazenil (0.01 mg/kg) was administered IV and resulted in immediate but transient improvement of clinical signs. The stuporous state returned after 60 min post-treatment and an additional dose of IV flumazenil (0.01 mg/kg) was administered with the same outcome. Based on this positive clinical response, IV infusion of flumazenil was initiated at 0.01 mg/kg/h following a loading dose of 0.005 mg/kg. Due to minimal improvement in neurological signs, flumazenil IV infusion was increased gradually until reaching the effective dose of 0.1 mg/kg/h. Flumazenil IV infusion was continued for 24 hours with improvements in neurological signs, which did not return upon gradual decrease of the flumazenil dose. This is the first report describing the use of a flumazenil IV infusion to improve neurological signs in a cat with a PSS and HE treated with diazepam.