European Journal of Anaesthesiology 2007; 24: 235–238 r 2007 Copyright European Society of Anaesthesiology doi: 10.1017/S026502150600202X Original Article Comparison of diphenhydramine and lidocaine for prevention of pain after injection of propofol: a double-blind, placebo-controlled, randomized study S. Apiliogullari * , B. Keles y , B. Apiliogullari z , M. Balasar z , H. Yilmaz y , A. Duman J * Ozel Konya Hospital, Department of Anaesthesia and Intensive Care; y Selcuk University, Medical Faculty, Department of Otorhinolaryngology; z Meram Teaching & Research Hospital, Department of Thoracic Surgery; z Ozel Konya Hospital, Department of Urology; y Ozel Konya Hospital, Department of General Surgery; J Selcuk University, Medical Faculty, Department of Anaesthesia and Intensive Care, Konya, Turkey Summary 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 5 0.00). No difference was found between the diphenhydramine and lidocaine groups (P 5 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. Keywords: PROPOFOL; LIDOCAINE; DIPHENHYDRAMINE; INJECTIONS INTRAVENOUS, adverse effects, pain. Introduction Propofol is a general anaesthetic agent that is widely used for induction of anaesthesia. It has a rapid onset of action with a dose-related hypnotic effect. Recovery is rapid even after prolonged use [1,2]. However, it causes pain or discomfort at the injection site in 28–90% of patients [3].A number of techniques have been used to minimize propofol-induced pain with variable results [4]. After reviewing more than 6000 patients in a trial for prevention of propofol injection pain, the most effective method is considered to be the use of a tourniquet and prior injection of lidocaine [1]. Diphenhydramine is an antihistamine that also has local anaesthetic properties [5]. There is no reported study to date in the litera- ture that uses diphenhydramine to reduce the prevalence and severity of propofol injection pain. This randomized, double-blind, placebo-controlled study was designed to compare the effectiveness of diphenhydramine and lidocaine on preventing propofol-induced injection pain. Correspondence to: Seza Apiliogullari, Department of Anaesthesia and Intensive Care, Ozel Konya Hospital, Konya, Turkey. E-mail: sapiliogullari@yahoo.com; Tel: 190 505 4887014; Fax: 190 332 3536431 Accepted for publication 13 October 2006 EJA 4012 First published online 4 January 2007