OnabotulinumtoxinA improves tactile and mechanical pain perception in painful diabetic polyneuropathy

Diabetic neuropathic pain may be relieved by onabotulinumtoxinA (BoNT/A). However, whether BoNT/A changes sensory perception in neuropathic patients remains unknown. This study used a double-blind crossover design to explore the possible effect of BoNT/A on sensory perception.

Eighteen patients with painful diabetic polyneuropathy underwent 2 consecutive 12-week periods of treatment either in the sequence of saline (control) and then BoNT/A (SB cohort, n=9) or BoNT/A followed by saline (BS cohort, n=9). Sensory perception was assessed according to the tactile threshold [TT, logarithmized force (g) of von Frey filaments] and mechanical pain threshold [PT, logarithmized weight (g) of weighted syringes], both being averages from 4 individual measurements of bilateral medial and lateral feet obtained at baseline (before injections) and at weeks 1, 4, 8, and 12 after treatment.

In either the SB or the BS cohort, there was a decrease in the TT and the PT after treatment with BoNT/A but not with saline. In the analysis merging both cohorts (n=18), BoNT/A resulted in a significant decrease in TT and PT at weeks 1, 4, 8, and 12 (all Ps<0.05 vs. saline). The longitudinal effect of BoNT/A on TT and PT remained significant when baseline values, treatment sequences, and periods were controlled using generalized estimating equations.

BoNT/A may improve tactile and mechanical pain perception in painful diabetic polyneuropathy. The beneficial effects of BoNT/A deserves further study to elucidate the exact mechanism and potential for preventing insensate injuries.