Although being well-tolerated, the 0.075% capsaicin lotion was not successful in showing any benefit compared to placebo in patients with PDN (Painful Diabetic Neuropathy).

Investigators conducted a randomized, double-blinded, placebo-controlled trial to evaluate the efficacy and safety of 0.075% capsaicin lotion for treating painful diabetic neuropathy (PDN).

The PDN subjects were randomized to receive 0.075% capsaicin/placebo for eight weeks, then crossing over to the other treatment following a 4-weeks washout period. Primary endpoint depicted a change in visual analogue scale score of pain severity. Secondary outcomes comprised of score changes in Neuropathic Pain Scale, short-form McGill Pain Questionnaires, and proportions of patients with pain score reductions varying from 30% to 50%, and the adverse events.

Forty-two subjects were enrolled, out of which 27 completed at least an 8-week treatment period. The intention-to-treat analysis revealed no significant improvement in pain control with capsaicin lotion as compared to the placebo for all the pain measures and proportion of patients who had 30% to 50% pain relief. Per protocol analysis were consistent. Capsaicin lotion was well tolerated; still, the local skin reactions were common.

In patients with PDN, the efficacy of 0.075% capsaicin lotion was similar to placebo but was well tolerated. More work is needed to assess different capsaicin formulations.