Anruikefen is a peripherally highly selective kappa receptor agonist that does not easily cross the blood-brain barrier, resulting in a low incidence of central adverse reactions such as respiratory depression, sedation, and addiction. As a Class 1 new drug, it was approved for marketing in China on May 13, 2025, and is indicated for the treatment of postoperative pain following abdominal surgery. Results from two Phase Ⅲ randomized controlled trials (RCTs) of Anruikefen have demonstrated its significant analgesic efficacy, with the incidence of postoperative nausea and vomiting (PONV) being 50% significantly lower than that in the placebo group, which confirms the favorable safety profile of Anruikefen Injection.

Therefore, this investigator-initiated trial (IIT) is designed to further verify the efficacy and safety of Anruikefen in patients undergoing total laparoscopic distal gastrectomy for gastric cancer.

Inclusion Criteria:

• Aged between 18 and 70 years old (inclusive).
• American Society of Anesthesiologists (ASA) physical status classification Class I-III.
• Body Mass Index (BMI) ranging from 18 kg/m² to 30 kg/m² (inclusive).
• Patients scheduled for elective total laparoscopic distal gastrectomy for gastric cancer under general anesthesia, with surgical duration < 5 hours.
• Surgical incision length < 8 cm.
• Voluntarily agree to participate in the trial and sign the informed consent form.

Exclusion Criteria:

• Patients undergoing emergency surgery or suffering from trauma.
• Patients who undergo conversion to open surgery or laparoscopically assisted distal gastrectomy for gastric cancer during the operation.
• Patients who refuse to receive Patient-Controlled Intravenous Analgesia (PCIA).
• Patients with a history of prior abdominal surgery.
• Patients expected to require prolonged endotracheal intubation after surgery.