摘要Background Sedatives and analgesics are often administered to achieve conscious sedation for diagnostic and therapeutic procedures. Appropriate concerns have been raised regarding post procedure delirium related to peri-procedural medication in the elderly. The objective of this study was to investigate the effect of premedication on new onset delirium and procedural care in elderly patients. Methods Patients≥70 years old and scheduled for elective cardiac catheterization were randomly assigned to receive either oral diphenhydramine and diaze-pam (25 mg/5 mg) or no premedication. All patients underwent a mini mental state exam and delirium assessment using confusion assess-ment method prior to the procedure and repeated at 4 h after the procedure and prior to discharge. Patients’ cooperation during the procedure and ease of post-procedure were measured using Visual Analog Scale (VAS). The degree of alertness was assessed immediately on arrival to the floor, and twice hourly afterwards using Observer’s Assessment of Alertness/Sedation Scale (OAA/S). Results A total of 93 patients were enrolled. The mean age was 77 years, and 47 patients received premedication prior to the procedure. None of the patients in either group developed delirium. Patients’ cooperation and the ease of procedure was greater and pain medication requirement less both during and after the procedure in the pre-medicated group (P < 0.05 for both). Nurses reported an improvement with patient management in the pre-medicated group (P=0.08). Conclusions In conclusion, premedication did not cause delirium in elderly patients undergoing cardiac catheterization. The reduced pain medication requirement, perceived procedural ease and post procedure management favors premedication in elderly patients undergoing cardiac catheterization.