Background: Topical capsaicin therapy may be of benefit in providing pain relief in patients
with peripheral neuropathy.
Objectives: To investigate the efficacy and safety of 0.625% (50 µg/cm2
) and 1.25%
(100 µg/cm2
) capsaicin patches (CPs) compared to conventional 0.075% capsaicin cream or
placebo patches in patients suffering from peripheral neuropathy.
Study Design: Early Phase II, multi-center, randomized, semi-double-blind, and placebocontrolled clinical trial.
Setting: Two medical college teaching hospitals.
Methods: Sixty patients were randomized to the 0.625% CP, 1.25% CP, placebo-controlled
patch, or 0.075% capsaicin cream. The primary efficacy endpoint was the mean difference
in the change of daily numerical rating scale (NRS) pain score. Secondary endpoints included
values for the Daily Sleep Interference Scale, the percentage of patients achieving a ≥ 30%
or ≥ 50% reduction in pain, and data for Global Impression Change (GIC) and EQ-5D.
Results: Patients treated with the 0.625% CP and 0.075% capsaicin cream showed
statistically significant improvements in pain after 6-weeks of test drug application. Daily
sleep disorder scores were improved only for those patients applying the 0.075% capsaicin
cream. For patient-derived GIC scores, the majority (11 of 12) of patients in the 0.625%
CP group reported that their pain was improved. For the safety evaluation, 2 severe
adverse events were reported for the 0.075% capsaicin cream group only. Repetitive patch
application was related to minor skin problems such as a burning sensation, erythema,
pruritus, and vesicles in 28 patients (46.67%).
Limitations: The small sample size and relatively high dropout rates.
Conclusion: Our data indicate that the 0.625% CP may prove to be an effective and safe
alternative with which to treat patients with peripheral neuropathy and could replace the
high concentration (8%) CP. Further studies are now needed to definitively establish efficacy.
Key words: Capsaicin, patch, CP, topical capsaicin, neuropathic pain, peripheral
neuropathic pain, PNP, high concentration CP
Topical capsaicin (high concentration) for chronic neuropathic pain in adults
