Dexmedetomidine versus ketamine infusion to alleviate propofol injection pain: A prospective randomized and double-blind study

Background and Aims: The use of propofol as the most common induction agent and the high prevalence of propofol injection pain (PIP) highlight the significance of finding the ideal combination of drug, dosage and mode of administration of premedicants to alleviate PIP. A number of bolus drugs with variable efficacy have been studied to reduce PIP. The aim of our study was to assess the efficacy of single dose intravenous (IV) infusion of dexmedetomidine 0.5 µg/kg compared with ketamine 0.5 mg/kg to alleviate PIP. Methods: In this prospective, randomised and double-blind study, 108 patients undergoing elective surgeries under general anaesthesia were randomly allocated to two groups: Group D to receive dexmedetomidine 0.5µg/ kg or Group K to receive ketamine 0.5 mg/kg in 20 ml of normal saline over 10 min. Immediately after the infusion, 1% propofol 2 mg/kg IV was injected over 25 s. The patients were assessed for pain every 5 s by asking the question ‘does it hurt?’ until the loss of consciousness. The pain scoring was done using McCririck and Hunter scale. Statistical analysis was done using SPSS 17.0. Results: The incidence of PIP and moderate-severe PIP was higher with Group D (79.6%; 16.7%) compared with Group K (40.7; 1.9%) (P < 0.001; 0.016). No patient in either group had arm withdrawal upon propofol injection. The incidence of hypertension and tachycardia was statistically significant in Group K as compared to Group D (P = 0.027). Conclusion: There was no difference in elimination of the arm withdrawal response and in incidence of moderate to severe PIP between the groups.