Background: HYR-PB21 is a new sustained-release formulation of bupivacaine indicated for controlling postoperative pain. The objectives of this study were to investigate the analgesic efficacy and safety profile of HYR-PB21 in patients after haemorrhoidectomy.
Methods: This was a multicentre, randomised, double-blind, positive-controlled trial. Patients were assigned randomly to receive a single dose of HYR-PB21 (150 mg or 300 mg) or bupivacaine HCl (75 mg) after surgery for prolapsing haemorrhoids. Postoperative pain was evaluated using a numeric rating scale at rest to calculate a cumulative pain score. Total rescue opioid usage and the proportion of subjects receiving rescue opioid were also assessed.
Results: We enrolled 72 patients with haemorrhoidectomy, and 71 patients completed the study. The average cumulative pain score through 72 h after surgery in the 300 mg HYR-PB21 group (87 scores) was lower than in the bupivacaine HCl group (166 scores) in an intention-to-treat analysis (P<0.001). There was a dose-response effect in reducing total opioid usage and the proportion of rescue opioid use between the 150 mg and 300 mg HYR-PB21 groups, with bupivacaine HCl as a reference group. The HYR-PB21 groups did not show more adverse effects than the bupivacaine HCl group.
Conclusions: Local infiltration of a single dose of HYR-PB21 sustained-release bupivacaine had better efficacy in controlling postoperative pain, with similar adverse effects, compared with a single dose of bupivacaine HCl in patients after haemorrhoidectomy.
Clinical trial registration: ChiCTR2000041318 (Chinese Clinical Trial Registry).
Keywords: analgesia; bupivacaine; haemorrhoidectomy; local anaesthesia; postoperative pain; sustained release.
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