The Effects of Intravenous Lidocaine on Pain During Injection of Medium- and Long-Chain Triglyceride Propofol Emulsions

In Brief Propofol formulated in medium- and long-chain tri-glycerides (MCT/LCT) is thought to cause less pain on injection. In this study we sought to determine if adding lidocaine to propofol-MCT/LCT is more effect-ive in decreasing pain compared with propofol-MCT/LCT alone or conventional propofol-lidocaine mixtures. Seventy-five patients were randomized into three groups. Group A received conventional propofol-lidocaine mixtures with 20 mg lidocaine, group B received propofol-MCT/LCT with saline, and group C received propofol-MCT/LCT with 20 mg lidocaine. The incidence of pain was 24% in groups A and B and 4% in group C. The number needed to treat to prevent pain was 5. We conclude that propofol-MCT/LCT-lidocaine mixtures significantly reduce pain. IMPLICATIONS: In this randomized, controlled, double-blind study, we found that the addition of 20 mg lidocaine to propofol (prepared in an emulsion of medium- and long-chain triglycerides) was effective in decreasing pain on injection.