Comparison of Propofol-Lipuro with propofol mixed with lidocaine 10 mg on propofol injection pain

A common drawback of propofol is pain on injection and lidocaine is commonly mixed with propofol to reduce its incidence and severity. We conducted a randomised, prospective, double-blind study to compare injection pain following the administration of two different formulations of propofol in 200 unpremedicated ASA I-III adult patients scheduled for elective surgery under general anaesthesia. Patients were allocated randomly into two groups to receive either Propofol-(R)Lipuro without added lidocaine or Diprivan(R-) mixed with lidocaine 10 mg. Five ml of the study solution was injected at a constant rate over 15 s and patients graded any associated pain or discomfort using a four-point verbal rating scale. The incidence of propofol injection pain was virtually identical in both study groups with 37/98 (38%) patients experiencing pain or discomfort following Propofol-(R)Lipuro compared with 35/98 (36%) after Diprivan(R) (p = 0.88). We observed no significant difference in pain scores between the groups (p = 0.67). Moderate or severe injection pain was experienced by 12/98 (12%) patients given Propofol-(R)Lipuro compared with 8/98 (8%) given Diprivan(R) (p = 0.48).