Baclofen intoxication in a dog successfully treated with hemodialysis and hemoperfusion coupled with intensive supportive care

To describe a case of confirmed baclofen intoxication in a dog that was successfully treated with hemodialysis and hemoperfusion (HD/HP) and to report the serum baclofen kinetics. A 2.5-year-old, 23 kg, spayed female Brittany Spaniel-mix was treated after ingesting 21-52 mg/kg of baclofen. The dog was comatose and was receiving manual ventilation at the time of presentation. Extracorporeal HD/HP was started 10 hours after admission. Within 3 hours of starting HD/HP the dog began initiating breaths and was extubated 18 hours after admission. Serial serum samples that were obtained during the first 24 hours of hospitalization were later analyzed for baclofen concentrations. The dog had elevated creatine phosphokinase and liver enzymes that correlated with an agitated recovery period. The dog had thrombocytopenia that resolved by 10 days after presentation. HD/HP shortened the baclofen serum elimination half-life from 5 to 1.5 hours in the initial 2 hours of treatment. The intrinsic elimination rate constant (K_intr) for this dog was 0.138/hour and the total elimination rate constant (K_tot) during the first 2 hours of HD/HP treatment was 0.458/hour. In this dog, HD/HP was an effective method for rapidly decreasing serum baclofen concentration after an acute overdose.