Prevention of pain on injection of propofol: a comparison of lidocaine with different doses of paracetamol.

Background And Objective: The aim of this study was to compare the efficacy of pretreatment with paracetamol 0.5 mg kg(-1), 1 mg kg(-1), 2 mg kg(-1) and lidocaine 0.5 mg kg(-1) for prevention of propofol induced pain.

Methods: In this double-blind, placebo-controlled study, 250 adult patients ASA I or II, scheduled to undergo elective surgery, were randomly assigned into five groups of 50 each. Group P0.5, group P1 and group P2 received 0.5, 1 and 2 mg kg(-1) paracetamol respectively; group L received 0.5 mg kg(-1) lidocaine; and the control group, group C, received isotonic saline pretreatment in the dorsum of the hand, followed by propofol 1 min later. A blinded researcher assessed the patient's pain level via a four-point scale.

Results: There were no significant differences in patient characteristics among the groups. The incidence of propofol injection pain in all treatment groups was significantly lower than in the control group (P < 0.001). When the paracetamol 0.5 mg kg(-1) group was compared with both the paracetamol 1 mg kg(-1) group (P < 0.01) and the paracetamol 2 mg kg(-1) group (P < 0.001), significant differences were observed. In the lidocaine 0.5 mg kg(-1) group propofol injection pain was significantly reduced compared with the paracetamol 0.5 mg kg(-1) group (P < 0.01). However, in the paracetamol 2 mg kg(-1) group pain was more significantly reduced than in the lidocaine 0.5 mg kg(-1) group (P < 0.001). In the paracetamol 2 mg kg(-1) group the incidence of pain was significantly less than in paracetamol 1 mg kg(-1) group (P < 0.001).

Conclusion: When given as venous retention pretreatments 1 min before propofol, paracetamol 1 mg kg(-1) and lidocaine 0.5 mg kg(-1) were equally effective in attenuating pain during intravenous (i.v.) injection of propofol whereas pretreatment with paracetamol 2 mg kg(-1) was shown to be the most effective treatment.