Comparative Analysis of Diphenhydramine and Lidocaine Wound Infiltration in Acute Postoperative Pain After Pyelolithotomy: A Randomized Controlled Trial

A key component of multimodal analgesia that enhances postoperative pain control is the wound infiltration of local anesthetics after surgery. Diphenhydramine is known to have local analgesic effects; however, it is unclear how well it works to lessen postoperative catheter-related bladder discomfort (CRBD) following pyelolithotomy. From 2022 to 2024, 82 eligible patients participated in this double-blind randomized controlled trial. Participants were randomly assigned to receive either diphenhydramine (20 ml, 0.5%) or lidocaine (20 ml, 1%) for wound infiltration prior to closure. As the primary outcome, the Visual Analog Scale (VAS) for the recovery period and the first 24 h following surgery was assessed. There were no statistically significant differences in the baseline characteristics. VAS demonstrated that diphenhydramine offered pain relief similar to that of lidocaine during the postoperative period, with significantly lower scores at 18 h (<i>p</i> < 0.001). The occurrence of CRBD was markedly reduced in the diphenhydramine group (<i>p</i> < 0.001), as was the intensity of CRBD (<i>p</i> < 0.001). Furthermore, the diphenhydramine group exhibited a significant reduction in analgesia requirements and total opioid consumption (<i>p</i> < 0.001). Compared to lidocaine, diphenhydramine infiltration considerably lowers postoperative pain and the requirement for opioids while increasing sedation levels following pyelolithotomy surgery.