Equivalent outcomes during postoperative patient-controlled intravenous analgesia with lidocaine plus morphine versus morphine alone

To evaluate a possible opioid-sparing effect of intravenous lidocaine we conducted a randomized, double-blind clinical trial. Patients undergoing intraabdominal surgery under general anesthesia were treated with patient-controlled analgesia (PCA) in three groups: Group 1 (n = 100; morphine 1 mg/mL), Group 2 (n = 44; morphine 1 mg/mL plus lidocaine 10 mg/mL), and Group 3 (n = 51; morphine 1 mg/mL plus lidocaine 20 mg/mL). Pain was evaluated using a 0-10 visual analog scale in the postanesthesia care unit (PACU) during deep inhalation at 15 and 30 min, and at 1,2, and 4 h after arrival in the PACU, and continued after PACU discharge every 4 h for 36 h. Patients whose pain was more than 4/10 in the PACU received 2.5 mL of the respective solutions every 7 min until pain was less than 4/10; then PCA was started. The number of bolus and cumulative drug doses during the study were recorded. Along with pain intensity, we assessed vital signs and side effects. Time to acceptance of oral liquids was also determined. Adding lidocaine 10 or 20 mg/mL to PCA morphine 1 mg/mL. for acute pain treatment after abdominal surgery yielded no differences in opioid use, pain levels, or side effects.