Medetomidine, levo-methadone and diazepam as premedication for lumbosacral epidural anaesthesia in dogs

The effect of medetomidine (40 μg/ kg) together with levo-methadone (0.5 mg/kg) was evaluated in dogs as a sedative and analgesic premedication followed by a lumbosacral epidural block with mepivacaine 2% or bupi-vacaine 0.5% (0.3–0.5 ml/10cm crown-rump length). When sedation became insufficient in the course of surgery, additional diazepam (0.1–0.2 mg/kg) was administered. Only in 43% of the dogs could surgery be performed without additional sedation. Medetomidine and levo-methadone influenced the cardio-respiratory system markedly. Hypoxaemia as well as hypercarbia were evident. Diazepam had no additional effect on these respiratory changes. After surgery 19 dogs were given atipamezole, 18 received atipamezole and naloxone while 17 received no antagonists. In 10 out of the 19 dogs receiving only atipamezole, fits of excitability were seen, but those receiving atipamezole and naloxone had a quiet recovery.