Analgesic effects of a 5% lidocaine patch after cesarean section: A randomized placebo-controlled double-blind clinical trial

Abstract

Study objective: This study aimed to evaluate the analgesic effects of a 5% lidocaine patch in acute postoperative pain after cesarean section. Design: This is a prospective, randomized, double-blind study. Setting: After surgery, active and placebo patches were applied in the operating room, and patients were evaluated during their stay at the postoperative recovery room and at the hospital ward. Patients: Seventy-two women (18 years of age or older and American Society of Anesthesiologists status II) scheduled for cesarean section under spinal anesthesia were enrolled in the study. Interventions: Patients were randomly assigned to an intervention or placebo group. According to the assigned group, a 5% lidocaine patch or a placebo patch was applied 1 cm above and below the Pfannenstiel incision after the surgery. Measurements: The primary outcome was the pain score, evaluated using an 11-point numerical verbal scale in the first 36 h postoperatively. Secondary outcomes were the quality of recovery 24 h after surgery, consumption of rescue opioids, and the presence of adverse effects. Main results: Sixty-five women completed the study. The pain score was lower in the lidocaine group at 6 h (lidocaine group: 2.16 ± 1.71, placebo group: 3.21 ± 2.25; p = 0.031), 12 h (lidocaine: 1.58 ± 0.81, placebo: 2.24 ± 0.74; p = 0.001), 24 h (lidocaine: 0.74 ± 0.89, placebo: 1.94 ± 1.39; p < 0.0001), and 36 h (lidocaine: 0.48 ± 1.03, placebo: 1.68 ± 0.94; p = 0.001) after surgery. There were no differences in secondary outcomes during the follow-up period. Conclusion: The lidocaine patch reduced pain scores compared to placebo in the first 36 h after the surgery, despite no influence over opioid consumption, quality of recovery, or incidence of side effects.