Sedative and analgesic effects of medetomidine in Beagle dogs infected and uninfected with heartworm.

摘要

The sedative and analgesic effects of medetomidine were investigated in heartworm-infected (HW+) and uninfected (HW) Beagle dogs by i.v. and i.m. administration of 30 鎔/kg and 40 鎔/kg doses, respectively. Posture, response to noise and the pedal reflex were monitored. A procedure for mock radiographical positioning was performed to test its overall clinical use. Observation times were 0, 15, 30, 60, 90, 120 and 180 min. The times from injection until the dog could not stand on its feet (down time), from lateral to sternal recumbency (sternal recumbency time), and from sternal recumbency to rising again (rising time) were also noted. Medetomidine produced rapid sedation and analgesia by both routes. Down times for the i.m. and i.v. routes were similar, which verified the manufacturer's recommended doses. The HW+ dogs had shorter down times, probably owing to increased blood flow to the brain caused by adrenergic alpha-2 activity. Sternal recumbency and rising times did not differ between the groups, suggesting a similar metabolism. Sedation and analgesia were adequate for performing the procedure in all dogs. HW+ dogs showed less resistance to handling during the procedure than HW+ dogs. It was concluded that medetomidine is be a suitable agentfor short-term chemical restraint in dogs, even with subclinical heartworm infestation.