Painless injection of propofol: pretreatment with ketamine vs thiopental, meperidine, and lidocaine.

Propofol, a commonly used anesthetic, often causes pain on injection. Several methods have been described to reduce this pain, however, complete inhibition has not been achieved. Our randomized, placebo controlled, double blind study has been conducted to compare the analgesic efficacy of iv pretreatment of ketamine, meperidine, thiopental, lidocaine to minimize the injection pain of propofol. 125 patients ASA I and II were randomly allocated into 5 groups and received. Group K, ketamine 0.4 mg/kg; Group T, thiopental 0.5 mg/kg; Group M, meperidine 0.5 [corrected] mg/kg; Group L, lidocaine 1 mg/kg; Group S, saline 3 ml. All pretreatment drugs were made into 4 ml solutions and were accompanied by manual venous occlusion for 1 min, followed by tourniquet release and slowly IV administration of propofol. Pain was assessed with a four point scale. All treatment groups had a significantly lower incidence of pain than placebo group (p <0.05). However, it has been observed that pretreatment with ketamine was the most effective in attenuating pain associated with propofol injection (p <0.05). For painless injection of propofol, routine pretreatment with ketamine 0.4 mg/kg along with venous occlusion is recommended.