The main use of neuromuscular blocking drugs is to provide skeletal muscle relaxation for facilitation of intubation of the trachea and to improve surgical working conditions in the anaesthetised patients. A 2×ED95 dose of non-depolarising muscle relaxant is recommended to facilitate tracheal intubation. In practice, 90% suppression of the single twitch response is usually considered clinical evidence of adequate drug-induced skeletal muscle relaxation.