Comparison of clonidine and dexmedetomidine for short-term sedation of intensive care unit patients

Background and Objectives: Patients on mechanical ventilation in intensive care unit (ICU) are often uncomfortable because of anxiety, pain, and endotracheal intubation; therefore, require sedation. Alpha-2 agonists are known to produce sedation. We compared clonidine and dexmedetomidine as sole agents for sedation. Study Design: Prospective, randomized, controlled open-label study. Materials and Methods: A total of 70 patients requiring a minimum of 12 h of mechanical ventilation with concomitant sedation, were randomly allocated into two groups. Group C ( n = 35) received intravenous (IV) clonidine (1 μg/kg/h titrated up to 2 μg/kg/h to attain target sedation), and Group D ( n = 35) received IV dexmedetomidine for sedation (loading 0.7 μg/kg and maintenance 0.2 μg/kg/h titrated up to 0.7 μg/kg/h to achieve target sedation). A Ramsay Sedation Score of 3-4 was considered as target sedation. Additional sedation with diazepam was given when required to achieve target sedation. The quality of sedation, hemodynamic changes and adverse effects were noted and compared between the two groups. Results: Target sedation was achieved in 86% observations in Group D and 62% in Group C ( P = 0.04). Additional sedation was needed by more patients in Group C compared with Group D (14 and 8 in Groups C and D, respectively, P = 0.034), mainly due to concomitant hypotension on increasing the dose of clonidine. Hypotension was the most common side-effect in Group C, occurring in 11/35 patients of Group C and 3/35 patients of Group D ( P = 0.02). Rebound hypertension was seen in four patients receiving clonidine, but none in receiving dexmedetomidine. Conclusion: Both clonidine and dexmedetomidine produced effective sedation; however, the hemodynamic stability provided by dexmedetomidine gives it an edge over clonidine for short-term sedation of ICU patients.