Efficacy of Antibiotics for Chronic Low Back Pain With Disc Herniation: A Randomized Clinical Trial

Antibiotics are currently being recommended for chronic low back pain, particularly when treatments have failed, even though the evidence for their use is conflicting.

To examine the efficacy and safety of antibiotics for the management of chronic low back pain with disc herniation at 12 months.

A community-based, double-blind, placebo-controlled randomized clinical trial with telemedicine to recruit and follow up participants remotely was conducted. Participants aged 18 to 60 years with chronic low back pain and the presence of a disc herniation on magnetic resonance imaging (MRI) were randomized between January 20, 2016, and May 27, 2021. Data analysis was performed from June to November 2024.

Participants were randomly assigned to receive amoxicillin-clavulanate, 500/125 mg, or identical placebo twice per day for 90 days.

The primary outcome was pain intensity measured using the Low Back Pain Rating Scale (score range, 0-10, with 0 indicating no pain and 10 indicating worst pain imaginable) at 12 months.

Of 415 participants assessed for eligibility, 170 (mean [SD] age, 44.4 [10.8] years; 101 [59.4%] male) were randomly assigned to receive amoxicillin-clavulanate (n = 85) or placebo (n = 85), and 152 (89.4%) provided primary outcome data at 12 months. Treatment with amoxicillin-clavulanate did not result in greater pain reduction than placebo at 12 months (adjusted difference, 0.06; 95% CI, -0.58 to 0.70) or 3 months (adjusted difference, 0.34; 95% CI, -0.18 to 0.86), independent of baseline pain. One participant in each group experienced a serious adverse event that was assessed as possibly related to the intervention, with 34 participants (40.0%) in the amoxicillin-clavulanate group and 20 (23.5%) in placebo group reporting any adverse event. Prespecified subgroup analyses showed no differences in pain between groups in those with Modic changes (bone changes detected on MRI).

This randomized clinical trial did not demonstrate efficacy of antibiotic therapy for chronic low back pain and disc herniation, including a subgroup with Modic changes. These findings suggest that antibiotics should not be used in the management of chronic low back pain and provide important data to prevent their inappropriate and harmful use.

http://anzctr.org.au Identifier: ACTRN12615000958583.