From the Journals

Analysis: Gabapentinoids aren’t the answer to back pain



Treating chronic lower back pain with gabapentinoids carries risks of dizziness, fatigue, and other side effects, but there is little evidence of their efficacy, according to a meta-analysis.

First-line analgesic treatment of chronic lower back pain (CLBP) often brings insufficient relief, leading to second-line treatments with gabapentinoids such as gabapentin (GB) or pregabalin (PG). These drugs are effective for neuropathic pain, but in most cases, CLBP has no clear cause.

Long-term use of gabapentinoids for CLBP has been increasing, but it could carry the risk of side effects. That prompted Harsha Shanthanna, MD, of McMaster University, Hamilton, Ont., and his colleagues to analyze existing research to determine their efficacy and potential harms in the treatment of CLBP.

In the study, published online Aug. 15 in PLoS Medicine (14[8]:e1002369), the researchers identified randomized, controlled studies of GB or PG in CLBP. Eight studies were included in the qualitative analysis, and six in a quantitative analysis.

The authors converted pain relief expressed in numerical rating scale or visual analog scale into a common scale of pain relief.

A meta-analysis of trials that compared GB to placebo found a small reduction in pain in the GB group (mean difference, 0.22 units; 95% confidence interval [CI], –0.51-0.07). No studies compared PG to placebo. Three studies (n = 169) compared PG to an active comparator, and the comparator yielded better improvements in pain (mean difference, 0.42 units; 95% CI, 0.20-0.64). The quality of evidence was rated very low in both PG to comparator and GB to placebo.

No deaths or hospitalizations were reported in the studies. Rates of adverse events were higher in the gabapentinoid groups than in the placebo group, including dizziness (risk ratio, 1.99, 95% CI, 1.17-3.37; number needed to harm, 7), fatigue (RR, 1.85; 95% CI, 1.12-3.05; I2 = 0; NNH, 8), difficulties with mentation (RR, 3.34; 95% CI, 1.54-7.25; NNH, 6), and visual disturbances (RR, 5.72; 95% CI, 1.94-16.91; NNH, 6). The evidence was of very low quality for dizziness and fatigue, low for difficulties with mentation, and moderate with respect to visual disturbances.

Dizziness was more common in PG groups, compared with active comparators (RR, 2.70; 95% CI, 1.25-5.83; NNH, 11), although the quality of evidence was very low.

The study included only a small number of trials, which could lead to issues with heterogeneity, the investigators cautioned.

“Our review demonstrates that there is limited evidence on the use of gabapentinoids in nonspecific CLBP, and the existing evidence in the form of RCTs does not support their use,” the authors concluded.

The study was not funded, and the authors reported having no relevant financial disclosures.

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