Limited Evidence for the Effectiveness of Oxcarbazepine in Neuropathic Pain
Additional randomized controlled trials are necessary to assess the effectiveness of oxcarbazepine in painful diabetic neuropathy.
Evidence for the effectiveness of oxcarbazepine in painful diabetic neuropathy and other forms of neuropathic pain is limited, suggesting a need for more randomized controlled trials, according to a Cochrane Database of Systematic Reviews study.
For this systematic review, the results of 5 randomized controlled trials (n=862; minimum treatment duration, 6 weeks) investigating the effectiveness of oxcarbazepine vs placebo in patients of any age or sex with any form of neuropathic pain were evaluated.
Of the 3 trials that evaluated oxcarbazepine in patients with diabetic peripheral neuropathy (n=634), 1 trial reported a benefit associated with oxcarbazepine, with a higher percentage of patients from the oxcarbazepine group vs the placebo group reporting a 50% reduction in pain (34.8% vs 18.2%, respectively; risk ratio [RR], 1.91) and a 30% pain reduction (44.9% vs 28.6%, respectively; RR 1.57). The other 2 trials reported little or no benefit of oxcarbazepine relative to placebo and did not include statistics for inclusion in a meta-analysis.
The studies that evaluated oxcarbazepine in diabetic peripheral neuropathies were at high risk for bias due to incomplete outcome data, possible unblinding of participants due to obvious adverse events, and publication bias.
A clinical trial that evaluated oxcarbazepine in radiculopathy reported no improvement relative to placebo for the outcome of >50% pain relief from baseline. For trials evaluating oxcarbazepine vs placebo in mixed neuropathies, a higher percentage of patients had “improved” or “very much improved” pain in diabetic peripheral neuropathy (45.9% vs 30.1%, respectively; RR, 1.46; n=493) and radiculopathy (23.9% vs 14.9%, respectively; RR, 1.61; n=145). Evidence for these trials was deemed of very-low quality.
Across all trials, most adverse events were mild or moderate. Oxcarbazepine was associated with severe adverse events in the diabetic peripheral neuropathy trials compared with placebo (8.35 vs 2.5%, respectively; RR, 3.65; n=634) and in the radiculopathy trial (RR, 3.13; n=145).
The authors concluded that the results of the systematic review “found little evidence to support the effectiveness of oxcarbazepine in painful diabetic neuropathy, neuropathic pain from radiculopathy and a mixture of neuropathies.” They suggested that “more well-designed, multicenter [randomized controlled trials] investigating oxcarbazepine for various types of neuropathic pain are needed.”
Zhou M, Chen N, He L, Yang M, Zhu C, Wu F. Oxcarbazepine for neuropathic pain. Cochrane Database Syst Rev. 2017;12:CD007963. doi: 10.1002/14651858.CD007963.pub3