Comparison of diphenhydramine and lidocaine for prevention of pain after injection of propofol: a double-blind, placebo-controlled, randomized study.

BACKGROUND AND OBJECTIVE

Pain on injection is still a problem with propofol. The purpose of the study was to compare the effectiveness of diphenhydramine and lidocaine on pain caused by propofol at the site of injection.

METHODS

One hundred and eighty ASA I-II adults undergoing elective surgery were randomly assigned into three groups of 60 each. Group I (placebo) received 2 mL normal saline, Group II received 2 mL (40 mg) 2% lidocaine and Group III received 2 mL (20 mg) diphenhydramine intravenously (i.v.) during a 1-min venous occlusion, followed by propofol into a cephalic forearm vein of the antecubital fossa. Pain assessment was made immediately after propofol injection.

RESULTS

In the placebo group 25 (41.7%) patients experienced pain during propofol injection as compared to 2 (3.3%) and 3 (5.0%) in the lidocaine and diphenhydramine groups, respectively. The prevalence of pain and pain score were significantly less in both the lidocaine and diphenhydramine groups than in the placebo group (P = 0.00). No difference was found between the diphenhydramine and lidocaine groups (P = 0.60).

CONCLUSION

Previous injection of diphenhydramine with venous occlusion can be considered as an alternative to lidocaine for reducing the prevalence of pain caused by injection of propofol into peripheral veins.