Lidocaine Patch (5%) is No More Potent than Placebo in Treating Chronic Back Pain When Tested in a Randomised Double Blind Placebo Controlled Brain Imaging Study

Abstract

BackgroundThe 5% Lidocaine patch is used for treating chronic neuropathic pain conditions such as chronic back pain (CBP), diabetic neuropathy and complex regional pain syndrome, but is effective in a variable proportion of patients. Our lab has reported that this treatment reduces CBP intensity and associated brain activations when tested in an open labelled preliminary study. Notably, effectiveness of the 5% Lidocaine patch has not been tested against placebo for treating CBP. In this study, effectiveness of the 5% Lidocaine patch was compared with placebo in 30 CBP patients in a randomised double-blind study where 15 patients received 5% Lidocaine patches and the remaining patients received placebo patches. Functional MRI was used to identify brain activity for fluctuations of spontaneous pain, at baseline and at two time points after start of treatment (6 hours and 2 weeks).ResultsThere was no significant difference between the treatment groups in either pain intensity, sensory and affective qualities of pain or in pain related brain activation at any time point. However, 50% patients in both the Lidocaine and placebo arms reported a greater than 50% decrease in pain suggesting a marked placebo effect. When tested against an untreated CBP group at similar time points, the patch treated subjects showed significantly greater decrease in pain compared to the untreated group (n = 15).ConclusionsThese findings suggest that although the 5% Lidocaine is not better than placebo in its effectiveness for treating pain, the patch itself induces a potent placebo effect in a significant proportion of CBP patients.

Brain networks predicting placebo analgesia in a clinical trial for chronic back pain

“…A thorough examination of the data corroborated by several reports in the literature [13,24,28,29,35,49] demonstrated that 5% lidocaine relieves pain through a placebo effect. We also confirmed that the overall decrease in clinical pain was due to the use of the patch or treatment, and not a consequence of spontaneous remission in chronic pain because an untreated CBP group (observation only control) showed minimal change in back pain.…”

“…The present study is a reanalysis of data presented regarding the effects of 5% lidocaine on spontaneous pain of CBP [24]. In the latter study we showed that active treatment was not different from the placebo arm.…”

“…In a recent placebo controlled, double blind, clinical trial for 5 % lidocaine topical patch treatment we reported that the active treatment was not significantly different from placebo in its effectiveness for treating chronic back pain [24]. A thorough examination of the data corroborated by several reports in the literature [13,24,28,29,35,49] demonstrated that 5% lidocaine relieves pain through a placebo effect.…”

“…We also confirmed that the overall decrease in clinical pain was due to the use of the patch or treatment, and not a consequence of spontaneous remission in chronic pain because an untreated CBP group (observation only control) showed minimal change in back pain. The placebo patch treatment was effective in nearly half of the patients (independent of the type of treatment), while the remaining patients showed little or no change in back pain [24]. To investigate the mechanisms for this marked interindividual variability in pain relief with a placebo treatment, here we investigate brain functional connectivity differences between the two groups at baseline, testing the hypothesis that in CBP patients placebo responses are contingent on predispositions that may be captured with brain network properties.…”

Alternatives to Opioids in the Pharmacologic Management of Chronic Pain Syndromes: A Narrative Review of Randomized, Controlled, and Blinded Clinical Trials

“…A study by Hashmi et al randomized 30 patients to either a 5% lidocaine patch or placebo patch 48 . After 2 weeks of use, both lidocaine and placebo patch groups reported a greater than 50% decrease in pain, suggesting that there may be no independent efficacy of 5% lidocaine patch for CLBP, but there is also a large and significant placebo effect, and that 5% lidocaine patch is not statistically significantly superior to placebo.…”