Authors : Kazuhito Itamoto, Kazuhiro Hara, Kenji Tani, Munekazu Nakaichi, Masaru Okuda, Takeshige Otoi, Hisashi Inokuma and Yasuho Taura
Abstract: The effect of a non-depolarizing neuromuscular blocking drug, vecuronium, is reportedly potentiated by volatile anesthetics. In this study, the influences of Halothane (Hal), Isoflurane (Iso) and Sevoflurane (Sev) on the effect of vecuronium were investigated in dogs. Six treatment groups were established for 2 concentrations (1.2 and 1.8 MAC) of Hal, Iso and Sev, using 6 healthy beagles. After the induction of anesthesia with propofol, 0.1 mg kg-1 of vecuronium was administered and its blocking effect was observed and recorded over time employing Single Twitch (ST) and Train-of-Four (TOF) stimulations. Parameters, such as the recovery time and rate were calculated and compared among the anesthetics and between the concentrations. All anesthetics potentiated the muscle relaxant effect in a dose-dependent manner. The TOF recovery rate was significantly lower in the Sev 1.2 MAC than in the Hal 1.2 MAC group and significant differences were noted between the concentrations at recovery time points of T1, T2 and T3 in the Hal group. potentiation by Hal increased in a concentration-dependent manner, whereas that by Sev was strong from the low concentration. In addition, differences in the ST and TOF recovery rates suggested that the site in the neuromuscular junction involved in vecuronium potentiation by Hal is different from that involved in potentiation by Iso and Sev. It was also suggested that the potentiation may have been due to volatile anesthetic-induced changes in the affinity for the drug.
Kazuhito Itamoto, Kazuhiro Hara, Kenji Tani, Munekazu Nakaichi, Masaru Okuda, Takeshige Otoi, Hisashi Inokuma and Yasuho Taura, 2010. Influence of Volatile Anesthetics on Muscle Relaxant Effect of Vecuronium in Dogs. Journal of Animal and Veterinary Advances, 9: 1131-1136.