The Combination of Buprenorphine and Pregabalin in the Management of Peripheral Neuropathic Pain: A Phase IV, Randomized, Double-Blind and Placebo-Controlled Clinical Trial.

backgroundPharmacological combinations are commonly used for treating refractory neuropathic pain, although supporting evidence is lacking. Gabapentinoid-opioid combination is one of the most studied; however, their efficacy is inconsistent across clinical trials. This trial investigated the feasibility, effectiveness and safety of adding pregabalin to buprenorphine for managing this condition.

methodsThis single-center, phase IV, double-blind, placebo-controlled trial enrolled adults with peripheral chronic neuropathic pain, refractory to tricyclic antidepressants and/or serotonin-norepinephrine reuptake inhibitors. Participants were randomized to receive transdermal buprenorphine up to 20 mcg/day, plus pregabalin up to 300 mg/day (group C) or placebo (group M). Participants underwent a 3-week tolerability-based dose titration and a 6-week maintenance phase. Primary outcome was ≥ 30% average pain reduction at week 9.

resultsSixty individuals (66.7% female, 53 [45-58.5] years old) were enrolled. After titration, pregabalin dose was 100 mg/day for most group C participants (87%), and transdermal buprenorphine doses were similar between groups (p = 0.787). At week 9, ≥ 30% pain reduction was achieved by 38% in group C and 32% in group M (p = 0.942). Pain interference, mood, anxiety and quality-of-life scores did not significantly differ between groups. Baseline pain phenotype was not associated with primary outcome results. Side-effect frequencies were similar between groups, and no serious adverse events occurred.

conclusionsAdding pregabalin to transdermal buprenorphine was not found to be effective for treating neuropathic pain. However, low-to-moderate analgesic effects cannot be excluded. Although no major side effects occurred, opioid use may have led to lower pregabalin tolerability, hindering the feasibility of this combination in clinical practice. SIGNIFICANCE STATEMENT: Although pharmacological combinations are widely prescribed for neuropathic pain (NP), consistent evidence of their benefit is lacking. This phase IV, pragmatic trial does not support the effectiveness of pregabalin-buprenorphine combination for refractory NP, even across distinct pain phenotypes. Besides suggesting the poor feasibility of this combination due to poor tolerability, it adds to the mounting evidence challenging earlier reports of an opioid-sparing effect for gabapentinoids. Clinical Study Registration Number: 52145215.0.0000.0068.