Intravenous lidocaine for the emergency department treatment of acute radicular low back pain, a randomized controlled trial.

BACKGROUND

Acute radicular back pain is a frequent complaint of patients presenting to the Emergency Department.

STUDY

OBJECTIVE

Determine the efficacy of intravenous lidocaine when compared to ketorolac for the treatment of acute radicular low back pain.

METHODS

Randomized double-blind study of 41 patients aged 18-55 years presenting with acute radicular low back pain. Patients were randomized to receive either 100 mg lidocaine or 30 mg ketorolac intravenously over 2 min. A 100-mm visual analog scale (VAS) was used to assess pain at Time 0 (baseline), and 20, 40, and 60 minutes. Changes in [median] VAS scores were compared over time (within groups) by the signed-rank test and between groups by the rank-sum test. A 5-point Pain Relief Scale (PRS) was administered at the conclusion of the study (60 min) and again at 1 week by telephone follow-up; [median] scores were compared between groups by rank-sum.

RESULTS

Forty-four patients were recruited; 41 completed the study (21 lidocaine, 20 ketorolac). Initial VAS scores were not significantly different between the lidocaine and ketorolac groups (83; 95% confidence interval [CI] 74-98 vs. 79; 95% CI 64-94; p = 0.278). Median VAS scores from baseline to 60 min significantly declined in both groups (lidocaine [8; 95% CI 0-23; p = 0.003]; ketorolac [14; 95% CI 0-28; p = 0.007]), with no significant difference in the degree of reduction between groups (p = 0.835). Rescue medication was required by 67% receiving lidocaine, compared to 50% receiving ketorolac. No significant change in PRS between groups was found at the conclusion or at the follow-up.

CONCLUSION

Intravenous lidocaine failed to clinically alleviate the pain associated with acute radicular low back pain.