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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

Pain for treated and observed groups, and pain when treated group was subdivided based on pain of CBP decreasing (CBPd) or persisting (CBPp) after 2 weeks. A. Pain at baseline and after 2-weeks (visual analog score, VAS, 0-10 score) in CBP patients who received no interventions or treatment instructions, CBP observed (n = 15), in contrast to the patients who participated in the clinical trial for an ineffective treatment, CBP treatment (n = 30). The two groups started at a similar intensity of back pain but only the CBP treatment group showed decrease in back pain after two weeks. Error bars represent SEMs. * p ≪ 0.05. B. Back pain intensity, in CBPd and CBPp groups, as a function of treatment duration. A median split shows that on average the group that showed absolute pain change more than the median had significantly lower pain at the 2 week time point.
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Figure 3: Pain for treated and observed groups, and pain when treated group was subdivided based on pain of CBP decreasing (CBPd) or persisting (CBPp) after 2 weeks. A. Pain at baseline and after 2-weeks (visual analog score, VAS, 0-10 score) in CBP patients who received no interventions or treatment instructions, CBP observed (n = 15), in contrast to the patients who participated in the clinical trial for an ineffective treatment, CBP treatment (n = 30). The two groups started at a similar intensity of back pain but only the CBP treatment group showed decrease in back pain after two weeks. Error bars represent SEMs. * p ≪ 0.05. B. Back pain intensity, in CBPd and CBPp groups, as a function of treatment duration. A median split shows that on average the group that showed absolute pain change more than the median had significantly lower pain at the 2 week time point.

Mentions: As a next step, we tested the hypothesis that a subset of susceptible CBP patients benefits more from Lidocaine treatment than the placebo treatment. For this analysis, first all subjects were separated objectively into two groups based on a median split. The median of the absolute change in pain in all subjects was 29.4. Thus, all subjects that showed more than median change in pain were designated to the CBP decreasing and those less than median pain change were assigned to the CBP persisting groups. Next, we investigated whether the percent change in pain differed between Lidocaine and placebo treated subjects within a subset of patients. There were eight placebo and 7 Lidocaine treated CBP subjects that had reported a more than median (median = 29.4) decrease in pain after 2 weeks of treatment and the mean percent change = 61.4%, SEM = 2.04. In the remaining subjects (below the median value) there were 7 placebo and 8 Lidocaine treated subjects and the mean percent change in this group was 3.9%, SEM = 0.13 (Figure 3B). Note that with this grouping, there was no difference in pain between the groups at the 6 hour time point (F1,29 = 2.7, p = 0.11).


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)

Pain for treated and observed groups, and pain when treated group was subdivided based on pain of CBP decreasing (CBPd) or persisting (CBPp) after 2 weeks. A. Pain at baseline and after 2-weeks (visual analog score, VAS, 0-10 score) in CBP patients who received no interventions or treatment instructions, CBP observed (n = 15), in contrast to the patients who participated in the clinical trial for an ineffective treatment, CBP treatment (n = 30). The two groups started at a similar intensity of back pain but only the CBP treatment group showed decrease in back pain after two weeks. Error bars represent SEMs. * p ≪ 0.05. B. Back pain intensity, in CBPd and CBPp groups, as a function of treatment duration. A median split shows that on average the group that showed absolute pain change more than the median had significantly lower pain at the 2 week time point.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 3: Pain for treated and observed groups, and pain when treated group was subdivided based on pain of CBP decreasing (CBPd) or persisting (CBPp) after 2 weeks. A. Pain at baseline and after 2-weeks (visual analog score, VAS, 0-10 score) in CBP patients who received no interventions or treatment instructions, CBP observed (n = 15), in contrast to the patients who participated in the clinical trial for an ineffective treatment, CBP treatment (n = 30). The two groups started at a similar intensity of back pain but only the CBP treatment group showed decrease in back pain after two weeks. Error bars represent SEMs. * p ≪ 0.05. B. Back pain intensity, in CBPd and CBPp groups, as a function of treatment duration. A median split shows that on average the group that showed absolute pain change more than the median had significantly lower pain at the 2 week time point.
Mentions: As a next step, we tested the hypothesis that a subset of susceptible CBP patients benefits more from Lidocaine treatment than the placebo treatment. For this analysis, first all subjects were separated objectively into two groups based on a median split. The median of the absolute change in pain in all subjects was 29.4. Thus, all subjects that showed more than median change in pain were designated to the CBP decreasing and those less than median pain change were assigned to the CBP persisting groups. Next, we investigated whether the percent change in pain differed between Lidocaine and placebo treated subjects within a subset of patients. There were eight placebo and 7 Lidocaine treated CBP subjects that had reported a more than median (median = 29.4) decrease in pain after 2 weeks of treatment and the mean percent change = 61.4%, SEM = 2.04. In the remaining subjects (below the median value) there were 7 placebo and 8 Lidocaine treated subjects and the mean percent change in this group was 3.9%, SEM = 0.13 (Figure 3B). Note that with this grouping, there was no difference in pain between the groups at the 6 hour time point (F1,29 = 2.7, p = 0.11).

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