A comparison of rocuronium and vecuronium: the pharmacodynamic, cardiovascular and intra-ocular effects

The aim of this study was to compare, in 30 patients, the pharmacodynamics of equipotent intubating doses of rocuronium and vecuronium and to compare their effects on heart rate, arterial pressure and intra-ocular pressure under steady state propofol anaesthesia. Baseline readings of heart rate and arterial pressure, using a Dinamap, and intra-ocular pressure, using a Tonopen, were made after induction of anaesthesia. The effects of the administration of the relaxants on these parameters were measured, recorded and compared. Rocuronium had a faster onset time than vecuronium, but had a similar duration of action. Vecuronium had no significant cardiovascular effects. Rocuronium caused a rise in mean arterial pressure (10-15%) and a slight rise in heart rate (5-10%). Both vecuronium and rocuronium caused similar falls in intra-ocular pressure. With its rapid onset time and lack of intra-ocular pressure effects, rocuronium is perhaps the relaxant of choice in patients with penetrating eye injuries requiring emergency endotracheal anaesthesia where a longer-acting relaxant is not contraindicated.