50% magnesium sulphate versus 2% lignocaine for amelioration of pain on injection of propofol – A single blind study

Introduction: Propofol has surmounted it's place in day care and ambulatory surgeries. However pain on propofol injection (POPI) still remains bothersome to most patients. Umpteen measures have been tried with variable results. In our study, 50% Magnesium sulphate with its unique and advantageous clinical profile was compared with the proven control, intravenous local anaesthetic 2% lignocaine to test their efficacy in reducing propofol induced pain. Aims: To compare pre-treatment of intravenous 50% magnesium sulphate and intravenous 2% lignocaine (preservative free) as an effective method in controlling POPI. Settings and Design: A sample of 100 patients of age 15-60 years belonging to ASA I and II posted for elective surgeries performed under general anaesthesia were allotted randomly into two groups. Methods and Material: In Group M, 50% MgSO4 1ml (500mg) and in Group L, 2% Lignocaine 1ml (20mg) was used administered. The patients were observed for pain on injection at 5, 10, 15 and 20 s with injection of propofol. Pain was assessed using a four point scale. Quantitative data collected was assayed using chi-square test. Results: There was no significant difference in the pain scores between both the groups (P value=0.6463). Conclusions: 50% MgSO4 is equally effective as 2% lignocaine in prevention of POPI and is a useful alternative for the same. No significant side effect were noted with the use of these drugs.