Rocuronium bromide can elicit a high incidence of pain when administered by intravenous injection. Several methods have been suggested to minimize the incidence and severity of this pain. In this study, we evaluated the quantitative effect of ketamine pretreatment on the incidence and severity of pain induced by intravenous rocuronium.

Sixty healthy female patients scheduled for general anesthesia were randomly divided into three groups; a saline group (n = 20), a ketamine 0.2 mg/kg group (n = 20), and a ketamine 0.5 mg/kg group (n = 20). Each patient received 2 ml of pretreatment solution via an 18 G angiocatheter inserted in a hand dorsal vein. After 30 seconds, 0.6 mg/kg of rocuronium bromide was administered intravenous. Anesthesia was induced by 2 mg/kg of propofol. Pain was assessed during rocuronium injection and pain severity was classified as none, mild, or severe.

The incidence of pain was significantly lower in the ketamine 0.5 mg/kg group than in the saline or ketamine 0.2 mg/kg groups. Patients administered ketamine at 0.2 mg/kg were found to be less likely to suffer severe vascular pain than those in the saline group.

Pretreatment with intravenous ketamine 0.5 mg/kg is more effective than ketamine 0.2 mg/kg at alleviating the incidence and severity of pain associated with rocuronium injection without significant side effects.