Transdermal buprenorphine relieves neuropathic pain: A randomized, double-blind, parallel-group, placebo-controlled trial in diabetic peripheral neuropathic pain

Abstract

OBJECTIVE To evaluate the efficacy and safety of transdermal buprenorphine in patients with diabetic peripheral neuropathic pain (DPNP). RESEARCH DESIGN AND METHODS This multicenter, randomized, double-blind, placebo-controlled, parallel-group trial enrolled patients with type 1 or type 2 diabetes and stable glycemic control who had been experiencing moderate to severe DPNP for at least 6 months on maximal tolerated conventional therapy. Patients were randomly assigned to receive buprenorphine (5 μ/h) or placebo patches. The dose was titrated to effect to a maximum of 40 μ/h. Paracetamol was available as rescue analgesia. The severity of pain and other symptoms of DPNP were assessed daily in a patient diary and at clinic visits. RESULTS One hundred eight-six patients were enrolled, with 93 randomized to either buprenorphine or placebo. A high proportion of patients did not complete the study (buprenorphine 37 of 93, placebo 24 of 93). The main reason for premature withdrawal in the buprenorphine group was adverse events commonly due to untreated nausea and/or vomiting. Among the per-protocol population, more patients in the buprenorphine group (86.3%) experienced a 30% reduction in average versus baseline pain at week 12 than those in the placebo group (56.6%, P < 0.001). A nonsignificant trend favored the buprenorphine groupwithin the intention-to-treat analysis of the same end point (51.7% vs. 41.3%, P = 0.175). CONCLUSIONS Transdermal buprenorphine,when tolerated, is an effective therapy for DPNP and provides another option tomanage this challenging painful condition. Nausea and constipation need to be managed proactively to optimize treatment outcomes.