Clinical Question

Are anticonvulsants an effective treatment for low back pain?

Bottom Line

The use of anticonvulsants like gabapentin (Neurontin) for painful conditions has increased greatly in recent years. This review finds good evidence that these drugs are not an effective treatment for low back pain with or without radiculopathy, and are associated with an increased risk of adverse events. (Level of Evidence = 1a)

Synopsis

Particularly in this era of heightened awareness of the potential harms of opioids, anticonvulsants are often prescribed for the treatment of painful conditions. Although there is evidence of their effectiveness, primarily for peripheral and diabetic neuropathy, anticonvulsants are increasingly prescribed for other conditions, including low back pain. This systematic review included a comprehensive search of the literature, and the authors identified nine randomized trials (three of which were crossover studies) that compared topiramate (Topamax), pregabalin (Lyrica), or gabapentin with placebo in patients with low back pain with or without radiculopathy. They excluded studies of pregnant women; preoperative patients; and patients with mixed conditions, such as neck and back pain. The trials were assessed for risk of bias, and only one was at high risk. The studies used a range of pain scales, so the standardized mean difference in pain scores between treatment and placebo groups was the primary outcome. The nine studies reported a total of 14 comparisons, with only two showing a statistically significant benefit. One was a small study of high-dose gabapentin (3,600 mg per day) in 43 patients with lumbar radicular pain, and the other was a study of topiramate (300 mg per day) in 96 patients with low back pain. The other studies of topiramate, pregabalin, or gabapentin found no benefit. Where results could be pooled, there was no difference between groups. There was no difference in serious adverse events: four in the pregabalin group and six in the placebo group (although these were reported in only two studies with a total of 423 patients). Any adverse events were significantly more common with active treatment (relative risk = 1.4; 95% CI, 1.2 to 1.7).

Study design: Meta-analysis (randomized controlled trials)

Funding source: Self-funded or unfunded

Setting: Various (meta-analysis)

Reference: Enke O, New HA, New CH, et al. Anti-convulsants in the treatment of low back pain and lumbar radicular pain: a systematic review and meta-analysis. CMAJ. 2018;190(26):E786–E793.

Editor's Note: Dr. Ebell is deputy editor for evidence-based medicine for AFP and cofounder and editor-in-chief of Essential Evidence Plus, published by Wiley-Blackwell.