Safety and efficacy of diphenhydramine as an adjunct to midazolam and fentanyl use for sedation in young patients undergoing endoscopic evaluation: a single-center retrospective study.

Background and Aims: Achieving adequate sedation may be difficult for young patients and can be associated with adverse events. Diphenhydramine (DPH) has not been studied in patients <45 years of age undergoing endoscopy. The aim of this study, therefore, was to evaluate the safety and efficacy of DPH as an adjunct to fentanyl/midazolam during endoscopy in this patient population. Methods: A retrospective, single-center cohort study was performed in patients aged 18 to 44 years who underwent EGD, colonoscopy, or both between 2020 and 2021. Patients who received DPH as an adjunct to fentanyl/midazolam (DPH group) were compared with those who received fentanyl/midazolam alone (non-DPH group). Outcomes included the incidence of adverse events, total facility time, total recovery time, total time to adequate sedation, and total sedation dose of midazolam and fentanyl used in both groups. Results: A total of 714 patients met the inclusion criteria: DPH group (n = 375) versus non-DPH group (n = 339). There was no difference in the incidence of adverse events ( Conclusions: This study found that DPH as an adjunctive sedative is safe and well tolerated in patients aged <45 years undergoing endoscopy and does not prolong the procedure or recovery time. Further prospective studies are needed to assess if DPH improves patient comfort, tolerance, and overall experience during endoscopic procedures.