Intravenous lidocaine does not provide additional pain reduction beyond placebo in probable nociplastic chronic low back pain: a randomized controlled equivalence trial.

In 30 seconds

This randomized, placebo-controlled equivalence trial assessed repeated intravenous lidocaine in 84 adults with chronic non-specific low back pain and probable nociplastic pain features. Participants received lidocaine or saline weekly for 4 weeks, alongside amitriptyline and aerobic exercise. At 3 months, the between-group difference in pain intensity was 0.24 VAS units (90% CI, -0.33 to 0.81), within the prespecified equivalence bounds of ±1.5, indicating no additional analgesic benefit from lidocaine. Both groups improved over time. Sleep quality improved more with lidocaine, while functional outcomes did not differ significantly.

Key findings

• At 3 months, the VAS difference was 0.24 (90% CI, -0.33 to 0.81), within the ±1.5 equivalence margin (TOST P < .001).
• Both groups improved over time, with no significant group × time interaction for pain.
• Sleep-quality improvement favored lidocaine (mean difference in change score, 1.81; 95% CI, 0.49-3.14; P = .027).
• Adverse events were more common with lidocaine but were mild, transient, and self-limiting.

Why it matters

The trial suggests that, when adults with probable nociplastic chronic low back pain receive multimodal management, repeated lidocaine infusions do not add meaningful pain relief over saline. The sleep-quality signal and numerically favorable functional findings do not establish broader benefit, particularly because continuous disability outcomes were not significantly different. These results help distinguish improvement during comprehensive care from an additional analgesic effect attributable to lidocaine.

What to keep in mind

The findings apply to lidocaine given alongside amitriptyline and aerobic exercise; the abstract does not establish its effects without this background management.