Propofol as an induction agent in children: pain on injection and pharmacokinetics

The efficacy of lignocaine (1%) mixed with propofol in reducing pain on injection with propofol was studied in 40 children undergoing elective surgery in a double-blind, randomized comparison with glucose (5%). The pharmacokinetics of propofol in a single dose of 2.5 mg/kg was also studied in eight children participating in the same study. Lignocaine (1 mg) significantly reduced pain on injection compared to the control group (P less than 0.001). The induction characteristics of propofol were not affected by the lignocaine, and no undesirable interaction was found between the two drugs. The first-stage elimination half-life (t1/2 beta) of propofol in children was shorter (mean 9.3 +/- 3.8 (s.d.) min) than the values found in adults. This pharmacokinetic alteration may have clinical significance following repeated administration or continuous infusion of propofol.