Perioperative Administration of Mirogabalin for Postoperative Pain Management Following Total Hip Arthroplasty: A Randomized Controlled Trial

BACKGROUND: Mirogabalin, a selective α2δ-1 ligand, has been proposed to exhibit potent analgesic effects with fewer central nervous system (CNS) side effects than prior gabapentinoids. Its effectiveness for acute postoperative pain after total hip arthroplasty (THA) remains uncertain. METHODS: This study was conducted as a prospective, single-center, open-label, assessor-blinded randomized trial. Adult patients undergoing primary THA were randomized in a 1:1 ratio to receive either oral mirogabalin (administered preoperatively, followed by 15 mg twice daily for two postoperative days; n = 44) or no additional drug (control group; n = 46). All patients also received standardized anesthesia and multimodal analgesia, including acetaminophen, nonsteroidal anti-inflammatory drugs, and fentanyl-based patient-controlled analgesia. The primary outcome was a cumulative 24-hour morphine equivalent consumption. The secondary outcomes included numeric rating scale pain scores at rest and during passive or active motion at two, four, 24, and 48 hours, as well as adverse events (drowsiness/sedation, headache, nausea, and vomiting). RESULTS: At 24 hours, morphine equivalent consumption was numerically lower in the mirogabalin group compared with the control group (14.6 ± 20.1 versus 22.0 ± 35.0 mg), but the between-group mean difference was not statistically significant (-7.42 mg; 95% confidence interval -19.44 to 4.60; Welch P = 0.223). Similarly, weight-normalized opioid use showed no difference. Repeated-measures analyses showed no significant between-group differences in numeric rating scale at any time point. The CNS-related adverse events were more frequent in the mirogabalin group, notably drowsiness/sedation (56.8 versus 28.3%; P = 0.01) and headache (13.6 versus 0%; P = 0.011), whereas nausea and vomiting did not differ. Early functional recovery was similar between groups. CONCLUSIONS: Perioperative mirogabalin did not reduce opioid consumption or postoperative pain after THA and was associated with an increased incidence of CNS-related adverse events. These findings do not support the routine use of mirogabalin as part of multimodal analgesia for primary THA. LEVEL OF EVIDENCE: Level 2.