Gabapentinoids ineffective in treatment of low back pain or lumbar radicular pain

Issue: October 2018

New research shows that the use of anticonvulsants for the treatment of low back pain or lumbar radicular pain is ineffective. The study, published in Canadian Medical Association Journal, also showed that the use of gabapentinoids had an increased risk of adverse events.

Perspective from Andrew J. Schoenfeld, MD, MSc

Oliver Enke

“Between 2013 and 2014, over 1.3 million prescriptions were written for the anticonvulsant medication pregabalin in Australia, and the prescription of anticonvulsants in primary care has increased by 535% in the last 10 years,” Oliver Enke, MBBS, MD, MSc, from the University of Sydney, told Healio Family Medicine. “We also conducted our own trial on the anticonvulsant drug pregabalin in patients with sciatica, which showed that pregabalin was not effective. This systematic review intended to gather evidence beyond our trial and see what the summary of evidence says.”

Enke and colleagues conducted a systematic review of nine placebo-controlled, randomized trials investigating the effects of anticonvulsants for low back pain and lumbar radicular pain. The trials included 859 unique patients and compared topiramate, gabapentin or pregabalin to placebo.

Of the 15 comparisons studied in these trials, 14 showed that anticonvulsants were ineffective in reducing back pain. The trials showed high quality evidence of no benefit from gabapentinoids vs placebo in the short term management of chronic lower back pain (pooled mean difference [MD] −0.0, 95% CI −0.8 to 0.7) or the intermediate term management of lumbar radicular pain (pooled MD −0.1, 95% CI −0.7 to 0.5).

Only seven of the studies included data on adverse events, one of which did not review gabapentinoids. The pooled results of the remaining six trials showed that that gabapentinoids were associated with an increased risk of adverse events most commonly drowsiness, dizziness and nausea, compared with placebo (pooled risk ratio [RR] 1.4, 95% CI 1.2 to 1.7.

“The take-home message is that anticonvulsants are not effective and can lead to adverse effects in people with low back pain and radiating leg pain (eg, sciatica), so they should not be recommended to this patient population,” Enke said.

He said that physiotherapy is something that should be considered early so patients stay active and mobile.

“The consensus recommendations for the treatment of nonspecific low back pain emphasize thorough patient education and advice to stay active,” said Enke. “Most often the symptoms improve over time and the patient can be reassured.” – by Jake Scott

Disclosures: Enke reports no relevant financial disclosures. Please see the full study for all authors’ relevant financial disclosures.

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Perspective

Andrew J. Schoenfeld, MD, MSc

The study in question was a meta-analysis evaluating outcomes and complications associated with the use of anticonvulsants, including gabapentinoids, for the treatment of low back pain. These are frequently used in clinical practice and, as the study reiterates, are known to have a verifiable complication profile. Their prescription is thus, not without risk to patients. What is important for clinicians to appreciate, however, is the inclusion criteria in the trials (and therefore also in the setting of this meta-analysis) are somewhat broad and the population is not homogeneous. There are obviously multiple clinical conditions that may lead to manifestations of chronic back pain (CBP) and, within the context of lower extremity symptoms, “sciatica” is not always synonymous with a true lumbar radiculopathy. Moreover, it is concerning to me there appears to be some conflation of radicular and neurogenic claudication type symptoms which is likely not clinically appropriate for application to orthopedic or spine surgical practice. These are distinct clinical entities with different physiologic etiology, pathophysiology and natural history. Therefore, I believe the recommendations regarding treatment should be applied cautiously and with careful consideration to the clinical characteristics of the patient in whom a prescription for anticonvulsants is being considered. Given the methodology, the findings may be more robust for individuals with non-specific CBP who have failed to respond to other treatment modalities. In individuals who present with true acute lumbar radiculopathy, and have concordant pathology on imaging, I think the literature supports other treatment options (as opposed to the use of anticonvulsants) as more effective choices.

Andrew J. Schoenfeld, MD, MSc

Associate professor

Director of Spine Surgical Research

Department of Orthopaedic Surgery

Brigham and Women’s Hospital

Harvard Medical School

Boston

Disclosures: Schoenfeld reports no relevant financial disclosures.

Sources/Disclosures

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Source:

Enke O, et al. CMAJ. 2018;doi:10.1503/cmaj.171333