NEW YORK (Reuters Health)—Solid evidence suggests that anticonvulsants provide no benefit for low back or lumbar radicular pain and a high risk of harm, researchers say.
“We started the study because these drugs were increasingly being used for low back pain and radiating leg pain, without the support of strong evidence of effectiveness,” principal investigator Dr. Christine Lin of the University of Sydney tells Reuters Health.
“I think the rate has soared because people want to avoid other strong medicines, such as opioids, and also because anticonvulsants are relatively new in their use for pain relief, thus offering a new option for people with pain,” she says by email. “In Australia, anticonvulsants were approved by the government for nerve pain in 2013.”
“We conducted our own trial on the anticonvulsant drug pregabalin in patients with sciatica, which showed that pregabalin was not effective,” she adds. “So the systematic review was to gather evidence beyond our trial and see what the summary of evidence says.”
Lead author Dr. Oliver Enke, also of the University of Sydney, notes in a separate email, “Our institution also investigated the prescription of analgesia for spinal pain, which concluded that general practitioners’ analgesic management of spinal pain has become increasingly divergent from guideline recommendations.”
“Between 2013 and 2014, over 1.3 million prescriptions were written for pregabalin in Australia,” he tells Reuters Health, “and the prescription of anticonvulsants in primary care has increased by 535% in the last 10 years.”
“The fact that anticonvulsants are often advertised to be effective for ‘nerve pain’ may mislead the prescriber to assume efficacy for low back pain or sciatica,” he says.
For the current study, online July 3 in CMAJ, Drs. Lin, Enke and colleagues analyzed nine placebo-controlled randomized trials with a total of 859 participants (average age about 51). Four trials included participants with chronic low back pain with or without radiating leg pain and five included participants with lumbar radicular pain.1
Fourteen of 15 comparisons found anticonvulsants were not effective in reducing the pain or disability of low back or lumbar radicular pain.
Specifically, high-quality evidence from three trials that investigated gabapentin versus placebo for chronic low back pain with or without radiating leg pain showed no effect for pain in the short term or for lumbar radicular pain in the immediate term.
Similarly, high-quality evidence showed gabapentin was ineffective in the intermediate term.
Moderate-quality evidence exists that topiramate provided a “small clinically worthwhile” effect in the short-term.
Further, “The lack of efficacy is accompanied by increased risk of adverse events from use of gabapentinoids, for which the level of evidence is high,” the authors conclude. The most common adverse events were drowsiness or somnolence, dizziness and nausea.
Dr. Lin notes, “What clinicians should do instead is to focus on the non-drug aspect of management.”
“Most people with low back pain and sciatica recover with time,” she says, “so the most important approach is to reassure patients of that, encourage them to stay active and avoid resting in bed.”
“Beyond that, if the pain persists, first try non-drug treatments such as physiotherapy,” she concludes.
Dr. Vijay Vad, a sports medicine specialist at the Hospital for Special Surgery in New York City, comments, “There is increasing scrutiny on narcotics, so physicians are looking for alternatives.”
“Pregabalin was approved for chronic pain and fibromyalgia (in the U.S.),” he tells Reuters Health. “When that happened, there was a huge marketing push and it got prescribed like crazy, along with its cheaper sister gabapentin.”
“I almost never prescribe pregabalin because of side effects like balance and dizziness issues, feeling ‘out of it,’ and weight gain,” he says by email.
- Enke O, New HA, New CH, et al. Anticonvulsants in the treatment of low back pain and lumbar radicular pain: A systematic review and meta-analysis. CMAJ. 2018 Jul 3;190(26):E786–E793.