It has been shown that dexmedetomidine was an efficacious and safe adjuvant in general anaesthesia. Administration of dexmedetomidine during the preoperative period has been demonstrated to reduce the requirement of opioid analgesics and other sedative and hypnotic drugs.Therefore, the study is designed to measure the effect of intravenous dexmedetomidine premedication on the propofol dose requirement and bispectral index at loss of consciousness.