Sedative effects of intramuscular administration of a low dose of romifidine in dogs

The sedative effects of i.m. administration of a low dose of romifidine were evaluated in 13 healthy adult Beagles. Physiological saline solution (0.2 ml), 0.1% romifidine (10, 20, or 40 micro g/kg) or 10% xylazine (1 mg/kg) was given i.m. in a crossover study design. Heart rate, respiratory rate, rectal temperature, haemoglobin saturation and scores for sedation, muscle relaxation, posture, auditory response and positioning response were recorded before and at regular intervals for up to 240 min after drug administration. Scores for sedation, muscle relaxation, posture, auditory response and positioning response increased in a dose-dependent manner after romifidine administration. Sedation induced by the highest dose of romifidine (40 micro g/kg) was comparable to that induced by xylazine (1 mg/kg). Heart rate, respiratory rate, and rectal temperature decreased in a dose-dependent manner after romifidine administration, but haemoglobin saturation did not change. It is concluded that romifidine (10, 20 or 40 micro g/kg, i.m.) is an effective sedative in dogs, but causes a decrease in heart rate, respiratory rate and rectal temperature..