Refinement of the dose of doxapram to counteract the sedative effects of acepromazine in dogs

Abstract

To evaluate the effectiveness of two doses of doxapram in reversing acepromazine sedation in dogs. Using a crossover design, 10 adult mixed-breed dogs received 0·05 mg/kg acepromazine, intramuscularly (im) followed 30 minutes later by one of the three randomly determined treatments: 0·0625 mL/kg saline, intravenously (iv), 1·25 mg/kg doxapram, iv or 2·5 mg/kg doxapram, iv. Sedation scores were obtained by a single, blinded observer at 0, 15 and 30 minutes after acepromazine administration and at 5, 15 and 30 minutes after the treatment administration. The mean baseline sedation score of all the treatments was not different among treatments. All the dogs had a significant increase in sedation score at 30 minutes after acepromazine administration. Both the low and high doses of doxapram showed a significant decrease in sedation score compared to saline, but there was no significant difference between the two doses. Five dogs in the high dose group panted after treatment injection, and this was significantly more than in the low dose group. Doxapram is effective in reducing the sedative effects of acepromazine over a short period of time. A dose of 1·25 mg/kg effectively decreases acepromazine sedation without causing panting.