Rocuronium (ORG 9426), an aminosteroid, with no metabolites, has a chemical structure similar to vecuronium (with active metabolites). Rocuronium has one eighth to one tenth the potency of vecuronium. The lesser potency of rocuronium produces a more rapid onset of block in comparison with equipotent doses of other drugs (., equal multiples of the ED 95 ) ( Kopman, 1989 ). Table 7-23 shows the ED 95 for infants and children for rocuronium. Bolus administration of mg/kg of rocuronium at two times ED 95 is associated with a transient increase in heart rate of about 15 beats/min and produces complete neuromuscular blockade (at the adductor pollicis) in infants and children in 50 and 80 seconds, respectively ( Woelfel et al., 1992; O'Kelly et al., 1994 ). Increasing the dose to mg/kg in children shortens this time to an average of 30 seconds ( O'Kelly et al., 1994 ). Low-dose rocuronium for tracheal intubation in children during inhalational induction is mg/kg (ED 95 ) and allows acceptable intubating conditions in 95% of children (aged 2 to 7 years) with sevoflurane anesthesia within 2 minutes, or in children (aged 1 to 3 years) of age in 60 seconds ( Eikermann et al., 2002 ). Another study shows that children (aged 4 to 6 years) have good intubation conditions in 90 seconds, 80% of the time ( Hung et al., 2005 ). Recovery to TOF of greater than occurs in 24 ± 8 minutes with a low dose of rocuronium ( mg/kg) ( Eikermann et al., 2002 ). Rocuronium mg/kg with halothane anesthesia in children (older than 1 year of age) shows a slower onset than the larger dose, but does not cause a prolonged block ( Driessen et al., 2002 ).