Safety and Efficacy of Fentanyl Versus Pethidine During Propofol-based Sedated Colonoscopy: Prospective Randomized Study

Inclusion Criteria: * A patient who undergo screening colonoscopy with sedative agents * A patient over 20 years and under 65 years * A patient who agree to participate in this study Exclusion Criteria: * A patient who is refered from outside hospital to remove previously noted colon polyp * The case who cannot be achieved cecal intubation because of poor bowel preparation * A patient who undergo sedative EGD just prior to colonoscopy * A patient who have allergy to propofol, pethidine, or fentanyl * A patient who have taken MAO inhibitor regularly * A patient who underwent colon resection surgery before colonoscopy * A patient who was diagnosed IBD before colonoscopy * Pregnant woman * A patient who cannot maintain sedation level because of significant cardiovascular disease, renal disease, pulmonary disease * A patient who do not agree to participate in this study * A patient who cannot understand this study because of foreigner or retarded mental status * A patient who have lower body weight, less than 37.5kg