Evaluation Of The Sedative Properties Of Different Doses Of Acepromazine And Acepromazine-Xylazine Combinations In Dogs

Acepromazine induces moderate sedation,possesses antiemetic,anticonvulsant and a decrease in spontaneous activity.It also effectively prevents cardiac dysrhythmia and ventricular fibrillation in dogs during the anesthesia,but this drug has no analgesic properties and not good candidates for excited dogs.Unlike acepromazine,xylazine has both profound sedative and some analgesic properties and can be used in excited and aggressive dogs.The effects are reversible with the selective a2-adrenergic antagonist.But,xylazine can inhibit the cardiovascular system,cause vomiting and cardiac arrhythmias after intramuscular injection of dog and cat.The peak effects of xylazine occur within 15 min,while 30 to 60 min should be allowed for maximal sedative effects to occur after injection of acepromazine.These experiments were performed to evaluate the effects of respiratory system,cardiovascular system and sedation of different doses of xylazine combined with acepromazine in dogs.Seven mixed breed dogs(three male and four females,weighing 7.6～11.2 kg)were divided into three groups.Each dog received 0.05 mg·kg-1 acepromazine(group A1),0.1 mg · kg-1 acepromazine(group A2)and 0.2 mg·kg-1 acepromazine(group A3),respectively.Heart rate(HR),respiratory rate(RR),mean arterial pressure(MAP),rectal temperature(RT)and sedative effect were measured before and after drug administration for 30,60,90,120,150 and 80 min.Results showed that group A1 had no obvious effect on heart rate,but group A2 or A3 declined the heart rate first and then increased.Three groups would decrease in respiratory rate,body temperature and MAP,the greater the dose of acepromazine was administrated,the more obvious adverse effect mentioned above represented,in which MAP of five dogs decreased to 60 mmHg in group A3.There were no significant differences of the peak sedative effect among three groups,which occured in 30 min after the adminstration,but duration of sedation was obviously prolonged with the increase of acepromazine dose.Acepromazine and xylazine are commonly used in clinics of small animal.This study was performed to evaluate the sedative effects of xylazine and acepromazine.Seven mixed breed dogs(three male and four females,weighing 7.6～11.2 kg)were divided into three groups.each dog received acepromazine 0.05 mg · kg-l(group A),xylazine 0.5 mg · kg-1+acepromazine 0.05 mg · kg-1(group AX),xylazine 0.5 mg · kg-1(group X).The heart rate(HR),respiratory rate(RR),rectal temperature(RT)and sedative effect were measured before and after drug administration for 30,60,90,120,150 and 180 min.Results showed that the sedative effect of group AX was stronger than the group A or X,and the onset time of group AX was shorter than the group A,duration of sedation and side effects in group AX were less than group X.In onclusion:high dose of acepromazine dosen’t increased the sedation in dogs,however,it’s will prolong the sedation time and increase the inhibition of cardiovascular and respiratory systems.The combination of acepromazine and xylazine induced high quality and deeper sedation in dogs than any of the two drugs used alone.