Effect of three doses of nalbuphine on reversal of sedation and cardiopulmonary effects of morphine-acepromazine in healthy dogs

Objective To evaluate the efficacy of three doses of nalbuphine in reversing sedative and cardiopulmonary effects of morphine-acepromazine in dogs. Study design Prospective, randomized experimental trial. Animals A group of eight healthy Beagle dogs, aged 5-6 years and weighing 12.5 +/- 2.1 kg. Methods Dogs were administered morphine (0.5 mg kg(-1)) and acepromazine (0.05 mg kg(-1)) intravenously (IV). After 20 minutes, dogs were administered one of four treatments IV: saline (control); or nalbuphine (0.3 mg kg(-1); treatment N0.3), (0.6 mg kg(-1); treatment N0.6) or (1.0 mg kg(-1); treatment N1.0), in random order separated by 1 week. Sedation was scored using a numeric descriptive scale (NDS) and simple numerical scale (SNS). Heart rate, systolic arterial pressure (SAP), respiratory rate (integral(R)) and rectal temperature (RT) were recorded before (BL), 20 minutes after morphine-acepromazine (T0), then 10 (T10), 30, 60 and 90 minutes after saline or nalbuphine. Arterial blood gases were measured at BL, T0 and T10. Values were compared with BL, T0 and among treatments using ANOVA (p < 0.05) and the Bonferroni correction (p < 0.008). Results NDS for N0.6 and SNS for N0.6 and N1.0 at T30, and both scores for all nalbuphine treatments at T60-T90 were lower compared with T0 (p < 0.05). Sedation scores were not different among nalbuphine treatments. SNS scores were lower than control at T10 for N0.3 and N0.6 (p < 0.05). SAP and f(R) were lower than BL for all treatments at some time points (p < 0.05). RT was higher than control at T60 in the nalbuphine treatments (p < 0.001). PaO2 was lower in N0.3 at T0 compared with BL (p = 0.036). Conclusions and clinical relevance All nalbuphine doses decreased the degree of sedation, without differences among them. Administration of nalbuphine resulted in minimal changes in measured cardiopulmonary variables.