Analgesic Effect of a 5% Lidocaine Patch in Patients With Opioid Treatment-Resistant Neuropathic Cancer Pain

Abstract PurposeLimited efficacy has been observed when using morphine to treat neuropathic pain. Lidocaine patches reduce neuropathic pain in post-herpetic neuralgia, but their benefits for cancer-related neuropathic pain remain unclear. This study aimed to demonstrate a useful treatment for cancer-related neuropathic pain. The primary endpoint was pain intensity evaluated by the visual analog scale (VAS). The secondary endpoints were the pain relief score and the quality of analgesic treatment. MethodsWe assessed the efficacy and safety of lidocaine patches in patients experiencing neuropathic cancer pain. Terminal cancer patients with opioid treatment resistance participated in the 3-day study. ResultsThe results showed a statistically significant difference in the median VAS over three days (Kruskal-Wallis test, P<0.0001). The median VAS pain intensity from Day 1 to Day 3 was 4.0 with 95% C.I. (3.3, 5.0), 3.0 (2.5, 3.5) and 2.5 (2.0, 3.0), respectively. The difference between the median VAS pain intensities of any two days was statistically significant (Wilcoxon signed-rank test, P < 0.0001). There was no statistically significant difference in the pain relief score or the quality of analgesic treatment. ConclusionIn this study, the 5% lidocaine transdermal patch reduced the VAS pain intensity in neuropathic cancer patients with morphine resistance. The transdermal patch is generally useful and well-tolerated.