I read with interest the article by Singh et al. [1] comparing propofol alone and in combination with ketamine or fentanyl for sedation during endoscopic ultrasonography. The combination of propofol and ketamine is used to confer advantages such as hemodynamic stability, analgesia, a lower incidence of respiratory depression, and faster recovery. The authors suggest the use of 50 μg fentanyl or 0.5 mg/kg ketamine in a single dose during endoscopic ultrasonography to reduce the dose of propofol required for sedation during the procedure. The dose of propofol administered was significantly higher in the propofol only group than in patients who received either fentanyl or ketamine as an adjuvant. However, in contrast to fentanyl, the use of ketamine prolonged the time to recovery (P < 0.001). The ketamine-propofol combination, also called ketofol, has been used for procedural sedation in several studies in varying ratios. Wang et al. [2] studied the use of the propofol-ketamine combination in varying ratios of 2 : 1, 3 : 1, and 4 : 1 and compared it with the propofol-fentanyl combination and propofol alone. They found that ketofol was as safe and effective as the propofol-fentanyl combination. The level of sedation and recovery based on discharge times for the 3 : 1 and 4 : 1 mixtures of ketofol were comparable to those for the combination of propofol with fentanyl 50 μg and propofol alone. The incidence of respiratory depression and post procedural drowsiness was lower with a 4 : 1 ratio (160 mg propofol and 40 mg ketamine) than with other ratios of ketofol. In another study, Gorji et al. [3] evaluated combinations of propofol with ketamine and fentanyl for endoscopic retrograde cholangiopancreatography. One group received ketamine 0.5 mg/kg, while the other group was administered fentanyl 50–100 μg. All patients received propofol 0.5 mg/kg followed by an infusion of 75 μg/kg/min. The level of sedation was equal in both groups (P > 0.05), while analgesia was better with fentanyl compared to ketamine (P < 0.05). Khajavi et al. [4] enrolled patients undergoing colonoscopy who were administered a combination of either fentanyl 0.5 μg/kg with propofol 0.5 mg/kg or ketamine 0.5 mg/kg with propofol 0.5 mg/kg (1 : 1 ratio). They found that patient satisfaction scores were significantly higher in the ketamine group. The level of sedation, hemodynamic status, oxygen saturation, incidence of nausea and vomiting, and recovery times were similar in both groups.