Clinical Study on the Effect of Tegileridine on Postoperative Pain in Patients Undergoing Abdominal Surgery.

Inclusion Criteria: * Adults 18-65 years; BMI 18-35 kg/m²; ASA physical status I-III. * Diagnosed with symptomatic gallbladder stone disease and scheduled for elective laparoscopic cholecystectomy under general anesthesia; expected procedure duration ≥60 minutes and postoperative hospitalization ≥24 hours. * Investigator expects moderate-to-severe postoperative pain; willing to receive standardized multimodal analgesia and protocolized rescue analgesia. * Able to understand pain scales (NRS/VAS) and provide written informed consent. * Women of childbearing potential: negative pregnancy test within 72 hours preoperatively and agreement to use effective contraception through 30 days after last dose. Exclusion Criteria: * Known hypersensitivity to opioids or any component of the study drug. * Chronic opioid use/tolerance (e.g., ≥30 mg MME/day for ≥7 consecutive days within 30 days pre-op) or current methadone/buprenorphine therapy. * Planned/required neuraxial analgesia (epidural/spinal), continuous peripheral nerve blocks, or use of long-acting local anesthetic formulations that would confound postoperative pain assessment; brief intraoperative wound infiltration with short-acting local anesthetics is allowed if standardized. * Significant respiratory disease (e.g., uncontrolled obstructive sleep apnea, GOLD III-IV COPD) or anticipated postoperative mechanical ventilation \>24 hours. ⑤Severe hepatic or renal impairment (Child-Pugh B/C; eGFR \<30 mL/min/1.73 m²; or ALT/AST \>3×ULN with total bilirubin \>2×ULN). ⑥Clinically unstable cardiovascular or cerebrovascular disease (e.g., shock, uncontrolled arrhythmias, myocardial infarction or stroke within 6 months), or persistent SBP \<90 mmHg. ⑦Concomitant medications that cannot be safely withheld: MAO inhibitors within 14 days; strong CNS depressants requiring continued use (e.g., benzodiazepines/barbiturates); mixed agonist-antagonist opioids (e.g., nalbuphine, buprenorphine) within 7 days. ⑧Severe psychiatric/neurologic disease or communication/cognitive impairment precluding valid pain scoring or follow-up. ⑨Pregnancy or breastfeeding; unwillingnebass to use contraception. ⑩Substance abuse (alcohol or drugs) within 12 months. ⑪Participation in another interventional study with study drug/device within 30 days. ⑫Any other condition that, in the opinion of the investigator, makes participation unsafe or impractical (e.g., severe active infection, planned ICU admission).