Transmucosal administration of pentobarbital and phenytoin solution induces euthanasia in bearded dragons (Pogona vitticeps)

Abstract

Abstract OBJECTIVE To assess the efficacy of transmucosal euthanasia solution to induce euthanasia. ANIMALS 6 bearded dragons (Pogona vitticeps). METHODS An initial dose of euthanasia solution containing pentobarbital and phenytoin sodium was administered transmucosally in conscious lizards (100 mg/kg pentobarbital dose), followed by a second dose 20 minutes later (400 mg/kg pentobarbital dose). The presence of movement, leakage of euthanasia solution, behaviors consistent with oral irritation, respiratory rate, heart rate, palpebral and corneal reflex, and response to noxious stimuli were recorded until death, confirmed by the absence of Doppler cardiac flow and cardiac electrical activity. The time to loss of all parameters was calculated. Postmortem evaluation allowed for histopathologic evaluation of the oral cavity and gastrointestinal tract to detect potential mucosal damage from the alkaline euthanasia solution. RESULTS The median time to death was 300 minutes (range, 300 to 360 minutes), median time to respiratory arrest was 30 minutes (range, 30 to 50 minutes), and median time to loss of deep pain response was 30 minutes (range, 20 to 50 minutes). Signs consistent with oral irritation occurred in 4 of 6 (66.7%) lizards, including 2 lizards that exhibited whole-body spasms after euthanasia solution administration. Histopathologic changes indicating peracute mucosal ulceration, suspected to be from caustic causes, were identified in 1 (1/6 [16.7%]) lizard. CLINICAL RELEVANCE Transmucosal euthanasia solution administration resulted in clinical euthanasia within 6 hours. This method should be utilized only after premedication with analgesic and/or anesthetic medications due to the potential for acute mucosal ulceration and behaviors that may be distressing in client-owned animals.