The Efficacy and Safety of Dexmedetomidine for Procedural Sedation in Patients Receiving Local Anesthesia Outside the Intensive Care Unit: A Prospective, Double-Blind, Randomized Clinical Phase III Trial in Japan

Background: Few studies (in other countries than the US) have reported on the efficacy and safety of dexmedetomidine for sedation of patients undergoing surgical or medical procedures under local anesthesia without intubation outside the intensive care unit. We performed a randomized, double-blind study in Japan. Methods: Adult patients were randomly allocated to receive placebo, dexmedetomidine 0.5 μg/kg (DEX 0.5 group), or dexmedetomidine 1.0 μg/kg (DEX 1.0 group) over 10 min. Then, both dexmedetomidine groups received dexmedetomidine 0.2–0.7 μg/kg/h for maintaining an Observer’s Assessment of Alertness/Sedation Scale (OAA/S) score of ≤ 4; however, propofol was administered to rescue patients whose score exceeded this value. The primary endpoint was the percentage of patients who did not require rescue propofol to achieve and maintain an OAA/S score of ≤ 4. Results: In total, 162 patients were included in the placebo (n = 53), DEX 0.5 (n = 53), and DEX 1.0 (n = 56) groups. Propofol was not required in significantly more patients in the dexmedetomidine 0.5 and 1.0 μg/kg groups (52.8% and 57.1%, respectively) compared with the placebo group (1.9%) (P < 0.001 for both). Common adverse events were protocol-defined hypotension, respiratory depression and bradycardia. The incidence of bradycardia was significantly higher in the DEX 0.5 (26.4%) and DEX 1.0 (30.4%) groups than in the placebo group (9.4%) (P = 0.041 and P = 0.008, respectively). Conclusion: We concluded that a loading dose of 0.5 or 1.0 μg/kg dexmedetomidine followed by infusion at a rate of 0.2–0.7 μg/kg/h provided effective and welltolerated sedation in patients undergoing surgical or medical procedures under local anesthesia without intubation. Clinical trials.gov identifier: NCT01438931