Palonosetron Pretreatment is not as Effective as Lignocaine for Attenuation of Pain on Injection of Propofol

OBJECTIVE: 5-HT3 receptor antagonists are known to possess local anesthetic properties and are commonly used for the alleviation of pain following propofol injection. Palonosetron, a newer molecule, has shown contradictory results for this property. The aim of this study was to compare the effect of palonosetron pretreatment in alleviating propofol injection pain with that of lignocaine. Their comparative effect on various hemodynamic parameters was also evaluated. METHODS: A total of 100 adult patients were randomly assigned to one of two groups: group L received lignocaine 40 mg in 5 mL of 0.9% saline pretreatment solution and group P received 0.075 mg palonosetron in 5 mL 0.9% of saline pretreatment solution. After 2 minutes, the tourniquet was released and one-fourth of the total calculated dose of propofol was administered, after which the pain assessment was made. The Students t-test was used for comparing the difference of mean between the two groups after testing for equality of variance using F-statistics. Categorical variables were expressed as a percentage, and the Chi-square test was performed to assess the independence of attributes. Repeated-measure analysis of variance was used to compare the change in heart rate and mean arterial pressure over three time points between the two groups. RESULTS: The proportion of pain reported by the subjects in the lignocaine group was significantly lower as compared to the subjects in the palonosetron group (p=0.001). No significant difference of mean heart rate and mean arterial pressure was observed between the two groups following these interventions. CONCLUSION: The efficacy of palonosetron in alleviating the pain on injection of propofol was significantly less than that of lignocaine.