Objective To compare the effects of remimazolam and dexmedetomidine on postoperative hyperalgesia and the inflammatory-oxidative stress response in elderly patients with benign prostatic hyperplasia （BPH） undergoing transurethral resection of the prostate， aiming to provide evidence for clinical anesthetic drug selection. Methods A total of 210 elderly patients with BPH who were scheduled for transurethral resection of the prostate at The Second Affiliated Hospital of University of South China from September 2024 to September 2025 were selected. By using a random number table， the patients were randomly divided into a control group （n = 105） and an observation group （n = 105）. The control group received an infusion of dexmedetomidine at a rate of 1.5 μg/（kg·h）， whereas the observation group was given an intravenous bolus of 0.2 mg/kg remimazolam. After anesthetic induction， both groups had their infusions adjusted to a continuous rate of 0.5 μg/（kg·h）. The quality of recovery at 24 h and 48 h post-operatively was assessed using the 15-item Quality of Recovery scale （QoR-15）， and cognitive function was evaluated preoperatively and on the third postoperative day using the Montreal Cognitive Assessment （MoCA）. The mechanical pain threshold （MPT） was measured preoperatively and at 24 h and 48 h postoperatively. Pain intensity was assessed using the Numeric Rating Scale （NRS） at 4， 12， 24， and 48 h postoperatively， and the total postoperative fentanyl consumption was recorded. Inflammatory markers including Tumor Necrosis Factor （TNF）-α， Interleukin （IL）-6， IL-17A， Interferon （IFN）-γ， IL-10， and High Mobility Group Box （HMGB） 1， as well as oxidative stress markers such as Superoxide Dismutase （SOD）， Glutathione Peroxidase （GSH-Px）， Catalase （CAT）， and Malondialdehyde （MDA） were measured before anesthesia （T?）， at the end of surgery （T?）， and at the end of anesthesia （T?）. The safety of the treatments was evaluated. Results Compared with the control group， the observation group exhibited significantly higher QoR-15 scores and MPT values at 24 h and 48 h post-operatively， as well as a higher MoCA score on the third postoperative day. Additionally， the observation group had significantly lower resting NRS scores at 4， 12， 24， and 48 h post-operatively， along with lower total fentanyl consumption. At T? and T?， the observation group showed significantly lower serum levels of TNF-α， IL-6， IL-17A， IFN-γ， HMGB1， and MDA， while the levels of IL-10， SOD， CAT， and GSH-Px were significantly higher （P < 0.05）. In terms of safety evaluation， the incidence of hypotension and bradycardia was significantly lower in the observation group （P < 0.05）. Conclusions For elderly patients with BPH who are undergoing transurethral resection of the prostate， remimazolam， when compared to dexmedetomidine， more effectively enhances the quality of postoperative recovery， safeguards postoperative cognitive function， relieves hyperalgesia and postoperative pain， decreases opioid consumption， exhibits superior suppression of the inflammatory response and oxidative stress， and is linked to a lower incidence of hemodynamic adverse events. Therefore， it can be regarded as a more ideal anesthetic option for this type of surgery.