High-dose oral pentobarbital can produce anesthesia in aggressive dogs prior to euthanasia

Objective: To determine whether PO administration of pentobarbital sodium solution at 3 times the labeled IV dose induces unconsciousness or euthanasia in dogs. Methods: 12 dogs met the inclusion criteria. Criteria included dogs in a shelter setting scheduled for euthanasia between June 2024 and October 2025. Dogs exhibiting human and/or animal aggression and scheduled for euthanasia were selected for the study. There were no limiting factors for inclusion such as breed, sex, or age. Results: Pentobarbital sodium solution was injected into size 00 gelatin capsules (1-mL capacity), placed in high-reward foods, and offered to the dogs; 9 consumed the food and 3 refused. Five of the 9 dogs that ate the food containing pentobarbital capsules (≥ 255 mg/kg) achieved unconsciousness within a mean time of 25 minutes. Respiratory rates remained slow but consistent during the observation period (120 minutes). All 12 dogs required another euthanasia method to achieve death. Conclusions: Ingestion of pentobarbital sodium as a euthanasia agent in dogs is unreliable. Death was not achieved 120 minutes after ingestion, and another euthanasia method was necessary. Clinical Relevance: Oral administration of ≥ 255 mg/kg of pentobarbital sodium appears to be an effective pre-euthanasia anesthetic for dogs. When handling is best avoided because of behavior, veterinary and animal shelter personnel may try offering pentobarbital sodium at high doses in capsules hidden in food to fasted dogs as an anesthetic agent before euthanasia.