Clinical observations on the use of the muscle relaxant rocuronium bromide in the dog

This study was designed to evaluate the effectiveness of neuromuscular blockade with rocuronium bromide (rocuronium) in eighty dogs anaesthetised for a variety of surgical procedures. Rocuronium 0.3 or 0.6 mg/kg (G03 and G06) was administered intravenously (IV) and neuromuscular function was monitored with an acceleromyograph. Lag time (LT) was >1 min in both groups. Onset time (OT) was 2 ± 0.9 and 1.1 ± 0.6 min in the groups given 0.3 and 0.6 mg/kg, respectively. There was a significantly longer time of action with 0.6 mg/kg in contrast to 0.3 mg/kg rocuronium. Time of no response (TonR) was 9.1 ± 4.9–16.9 ± 6.1 min in the groups given 0.3 and 0.6 mg/kg, respectively. The time from the end of injection until 25% recovery of the first twitch from the baseline value (T125) was 13.8 ± 5.5 and 22.3 ± 6.7 min in the groups given 0.3 and 0.6 mg/kg, respectively. T125–75 was similar in both groups. Total recovery to baseline values was achieved in 23.8 ± 6.6 and 31.9 ± 6.5 min in the groups given 0.3 and 0.6 mg/kg, respectively (P < 0.05). Premedication, maintenance agent, body position and stimulation site had no significant influence on the pharmacodynamic parameters in both groups. It was concluded that rocuronium is an effective non-depolarising muscle relaxant in the dog under clinical conditions.