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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.

Hashmi JA, Baliki MN, Huang L, Parks EL, Chanda ML, Schnitzer T, Apkarian AV - Mol Pain (2012)

Bottom Line: 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).These 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.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Physiology, Northwestern University, Feinberg School of Medicine, Chicago, Illinois 60611, USA.

ABSTRACT

Background: The 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).

Results: There 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).

Conclusions: These 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.

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Related in: MedlinePlus

Consort 2012 flowchart.
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Figure 4: Consort 2012 flowchart.

Mentions: A sample size of 30 subjects was predetermined based on a a review of literature [4,38]. A total of 38 patients were recruited for the brain imaging and treatment study. As shown in the consort flow chart shown in Figure 4, data from 7 subjects was not analyzed due to failure to attend the repeat sessions for non specific reasons and data from 1 subject was excluded from analysis due to technical faults. Thus, data from a total of 30 subjects (16 males, 14 females, age 51.36 ± 0.30 years, mean ± SEM) was included in the brain imaging analysis. An additional 15 patients (10 males, 5 females, age 46.3 ± 0.38 years) were recruited and their pain was measured at intervals similar to the patch treated groups. Brain imaging data was not collected in this group.


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.

Hashmi JA, Baliki MN, Huang L, Parks EL, Chanda ML, Schnitzer T, Apkarian AV - Mol Pain (2012)

Consort 2012 flowchart.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3475108&req=5

Figure 4: Consort 2012 flowchart.
Mentions: A sample size of 30 subjects was predetermined based on a a review of literature [4,38]. A total of 38 patients were recruited for the brain imaging and treatment study. As shown in the consort flow chart shown in Figure 4, data from 7 subjects was not analyzed due to failure to attend the repeat sessions for non specific reasons and data from 1 subject was excluded from analysis due to technical faults. Thus, data from a total of 30 subjects (16 males, 14 females, age 51.36 ± 0.30 years, mean ± SEM) was included in the brain imaging analysis. An additional 15 patients (10 males, 5 females, age 46.3 ± 0.38 years) were recruited and their pain was measured at intervals similar to the patch treated groups. Brain imaging data was not collected in this group.

Bottom Line: 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).These 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.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Physiology, Northwestern University, Feinberg School of Medicine, Chicago, Illinois 60611, USA.

ABSTRACT

Background: The 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).

Results: There 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).

Conclusions: These 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.

Show MeSH
Related in: MedlinePlus