Serum Baclofen Concentrations in Four Dogs With Baclofen Toxicosis Treated With In‐Series Carbon Hemoperfusion and Hemodialysis

OBJECTIVE: To report serum baclofen concentrations before, during, and after in-series carbon hemoperfusion (cHP) and hemodialysis (HD) in four dogs with severe baclofen toxicosis. SERIES SUMMARY: This series involves four dogs with serum samples collected before, during, and after in-series cHP/HD. The extraction ratio (ER, %) of cHP and HD, half-life during cHP/HD, and total extracorporeal elimination constant were calculated. Posttreatment samples were collected to determine endogenous half-life and intrinsic elimination constant. Two dogs received both cHP/HD and mechanical ventilation, while the other two received cHP/HD alone. The range of ingested dosages was 4-24 mg/kg. The median time from suspected ingestion to cHP/HD initiation was 7 h (range: 5-15 h). Extracorporeal therapy was performed using an intermittent hemodialysis platform in two cases and a continuous renal replacement therapy platform in two cases. The median duration of cHP/HD was 3 h (range: 2.2-4 h), with a median total blood volume processed of 1.3 L/kg (range: 1-1.5 L/kg), equating to 15 times (range: 12-18.2 times) the estimated blood volume (80 mL/kg) in dogs. Serum baclofen concentration was reduced during cHP/HD by a median 69% (range: 46%-80%). The median ER for cHP was 61% (range: 60%-81%) and for HD was 4% (range: -0.5% to 11.5%). The calculated half-life during cHP/HD was 1.9 h (range: 1.1-2.5 h), compared with 5.8 h (range: 3.1-13.6 h) after cHP/HD. The median extracorporeal elimination constant was 0.34 (range: 0.08-0.37), which was 2.8 times faster than the intrinsic elimination constant of 0.12 (range: 0.05-0.23). NEW OR UNIQUE INFORMATION PROVIDED: In-series cHP/HD reduced serum baclofen concentrations in this small series of dogs, highlighting its potential role in the treatment of severe baclofen intoxication.