Efficacy of azasetron on postoperative chronic pain after pulmonary surgery: a randomized triple-blind controlled trial

Abstract

Abstract Background Inhibition of 5-HT3 (5-Hydroxyl Tryptamine) receptors is known to enhance morphine analgesia in animal models. We tested the efficacy of azasetron, a 5-HT3 receptor antagonist, on postoperative chronic pain after pulmonary surgery in a randomized triple-blind controlled study. Methods A total of 250 patients who were scheduled to receive pulmonary surgery were randomized to patient-controlled analgesia (PCA) using 200 µg sufentanil with normal saline or 200 µg sufentanil with 20 mg azasetron. The numerical rating scale of pain (NRS) was recorded at baseline, postoperative day (POD) 1, 2, 3, 90, and 180. Negative binomial regression was used to identify associated factors for postoperative NRS six months after surgery. Results The results showed that azasetron did not affect the primary outcomes: the incidence of postoperative chronic pain on POD90 and 180. However, azasetron decreased postoperative NRS at rest and activity on POD1, 2, and 3. Furthermore, azasetron decreased postoperative nausea and vomiting on POD1 and 2. Univariate and multivariate negative binomial regression analysis identified preoperative pain, smoking, drinking and open surgery are risk factors of chronic pain six months after surgery. Conclusions Azasetron did not affect the incidence of chronic pain after pulmonary surgery. The presence of preoperative pain, smoking, drinking, and open surgery were found to be associated with chronic pain six months after surgery. Clinical trial registration The trial was registered prior to patient enrollment at the Chinese Clinical Trial Registry (ChiCTR2200060139), 20/05/2022; the site url is https://www.chictr.org.cn/.