Intravenous lidocaine bolus for reducing nefopam-induced venous pain: A randomized, intrasubject comparison trial

Intravenous nefopam reduces postoperative pain and opioid consumption but can cause infusion-related pain. We aimed to investigate whether lidocaine can effectively reduce this pain.

This prospective, randomized, double-blind, controlled, intrasubject comparison trial included 42 patients (20-60 years) undergoing elective surgery under regional or peripheral anesthesia. In the postanesthesia care unit, two 50 mL syringes containing nefopam (20 mg) diluted in saline (100 mL) were sequentially infused in 15 min into venous catheters in the left and right arms. Patients were randomly assigned to the "left side" or "right side" group based on the arm in which a bolus of 1% lidocaine (2 mL) (study group) was administered before nefopam infusion. Normal saline (2 mL) was administered on the control side. Numerical Rating Scale scores and the incidence of pain (scores > 3) and nausea or vomiting were recorded at 1, 5, 10, and 15 min.

The analysis included 42 patients (84 infusions). Compared with the placebo, lidocaine lowered the mean infusion-related pain at 1 (0.07 vs. 2.21, P < 0.001), 5 (2 vs. 4.21, P < 0.001), 10 (2.02 vs. 3.95, P < 0.001), and 15 min (1.62 vs. 3.16, P = 0.003). At 5 min, significantly higher percentages of infusion sites with moderate and higher pain scores (> 3) were observed on the control side (30.95% vs. 14.29%, P = 0.000). Seven patients exhibited nausea or vomiting (16.7%).

For the nefopam infusion rate and concentration that we used, a 20 mg lidocaine pretreatment bolus significantly reduces infusion-related pain.