Use of anti-convulsant drugs to treat low back pain has increased more than fivefold in the past decade, but a study finds they are ineffective and can have adverse effects.
“Clinically, the prescription of anti-convulsants for back and neck pain, including radicular pain in primary care, has increased by 535% in the last 10 years,” writes Dr Oliver Enke, University of Sydney, Sydney Medical School Nepean, Kingswood, Australia, with co-authors, citing data from a recent study on prescribing trends for back pain.
Low back pain affects millions of people and is the number one cause of disability. Clinical practice guidelines usually recommend non-pharmacologic treatments and non-opioid pain relievers rather than stronger analgesics such as anti-convulsants.
The study findings are based on high and moderate-quality evidence from 9 placebo-controlled randomized trials that found a lack of evidence of benefit from anti-convulsants and more adverse events from some of these drugs.
“We have shown, with mostly high- and moderate-quality evidence, that common anticonvulsants are ineffective for chronic low back pain and lumbar radicular pain, and are accompanied by increased risk of adverse events,” write the authors.
These findings support recent guidelines from the US and the UK that do not recommend the use of anti-convulsants.
Background: The use of anticonvulsants (gabapentin, pregabalin) to treat low back pain has increased substantially in recent years despite limited supporting evidence. We aimed to determine the efficacy and tolerability of anticonvulsants in the treatment of low back pain and lumbar radicular pain compared with placebo.
Methods: A search was conducted in 5 databases for studies comparing an anticonvulsant to placebo in patients with nonspecific low back pain, sciatica or neurogenic claudication of any duration. The outcomes were self-reported pain, disability and adverse events. Risk of bias was assessed using the Physiotherapy Evidence Database (PEDro) scale, and quality of evidence was assessed using Grading of Recommendations Assessment, Development and Evaluation (GRADE). Data were pooled and treatment effects were quantified using mean differences for continuous and risk ratios for dichotomous outcomes.
Results: Nine trials compared topiramate, gabapentin or pregabalin to placebo in 859 unique participants. Fourteen of 15 comparisons found anticonvulsants were not effective to reduce pain or disability in low back pain or lumbar radicular pain; for example, there was high-quality evidence of no effect of gabapentinoids versus placebo on chronic low back pain in the short term (pooled mean difference [MD] −0.0, 95% confidence interval [CI] −0.8 to 0.7) or for lumbar radicular pain in the immediate term (pooled MD −0.1, 95% CI −0.7 to 0.5). The lack of efficacy is accompanied by increased risk of adverse events from use of gabapentinoids, for which the level of evidence is high.
Interpretation: There is moderate- to high-quality evidence that anticonvulsants are ineffective for treatment of low back pain or lumbar radicular pain. There is high-quality evidence that gabapentinoids have a higher risk for adverse events.
Oliver Enke, Heather A New, Charles H New, Stephanie Mathieson, Andrew J McLachlan, Jane Latimer, Christopher G Maher, CW Christine Lin