Efficacy and safety of anrikefon injection for postoperative analgesia in specific patient groups (elderly, liver damage, renal damage) after abdominal surgery.

Abstract

Background: This study aims to evaluate the efficacy and safety of anrikefon for postoperative analgesia following abdominal surgery in specific populations, including elderly patients and those with mild to moderate kidney or liver injury.

Methods: A total of 387 patients aged 18-70, with a BMI of 18-40 kg/m², without severe systemic diseases, relative allergies, or recent analgesics use, and scheduled for abdominal surgery under general anesthesia between June and September 2022, were enrolled. Participants with a postoperative static pain score (numerical rating scale, NRS) of no less than 4 were randomly assigned to one of three groups: the anrikefon group (group A, anrikefon 1 µg/kg), the tramadol group (group T, tramadol 1 mg/kg) or the control group (group C). Three doses were administered every 8 hours. Subgroup analyses were specifically conducted for 46 elderly patients aged 65-70, 158 patients with mild to moderate kidney injury, and 83 patients with mild liver injury. General information of patients was recorded. NRS scores at 15 min, 30 min, 1 h, 2 h, 4 h, 8 h, 12 h, 16 h, 20 h, 24 h after first dose were documented. The primary outcome measure was the sum of pain intensity difference over 24 h (SPID_0-24h). Other measures include SPID_0-12h, pain intensity difference (PID), the ratio and accumulated doses as well as start time of rescue analgesia, incidence of nausea and vomiting, patient and researcher satisfaction scores, ratio of patients with NRS ≤ 3 at each time point during 12 h and 24 h periods.

Results: In elderly patients aged 65-70, pain reduction, as measured by SPID_0-24h, and SPID_0-12h, were significantly higher in group A compared to group C (P < 0.05), and the patient and researcher satisfaction scores were also significantly higher in group A (P < 0.05). In patients with mild to moderate kidney injury, SPID_0-24h and SPID_0-12h showed significant difference between group A and group C (P < 0.01). However, no statistical difference of SPID was observed between group A and T. Ratio and accumulated doses of rescue analgesia in group A and T were significantly lower than those in group C. Rescue analgesia was administered later in group A and T as compared to group C (P < 0.01). Ratio of patients with NRS ≤ 3 at each time point and researcher satisfaction score were higher in group A and C (P < 0.01). Patient satisfaction score in group A was higher than that in group T (P < 0.01). In patients with mild liver injury, SPID_0-24h and SPID_0-12h showed no statistical difference among three groups. However, the ratio and accumulated doses of rescue analgesia in group A were significantly lower than those in group C (P < 0.05). The proportion of patients with NRS ≤ 3 at each time point was higher in group A. Additionally, the incidence of nausea and vomiting in group A was lower compared to group T, regardless of the specific populations.

Conclusions: Anrikefon provides effective and safe postoperative analgesia following abdominal surgery for elderly patients, as well as for those with mild to moderate kidney injury and patients with mild liver injury.