Pain
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Randomized Controlled Trial Multicenter Study
Spinal cord stimulation in patients with painful diabetic neuropathy: a multicentre randomised clinical trial.
Painful diabetic neuropathy (PDN) is a peripheral neuropathic pain condition that is often difficult to relieve. Spinal cord stimulation (SCS) is a proven effective therapy for various types of mixed neuropathic conditions, yet effectiveness of SCS treatment for PDN is not well established. To our knowledge, ours is the first multicentre randomized controlled trial investigating the effectiveness of SCS in patients with PDN. ⋯ After 6 months of treatment, the average VAS score was significantly reduced to 31 in the SCS group (P<.001) and remained 67 (P=.97) in the control group. The SF-MPQ and EuroQoL 5D questionnaires also showed that patients in the SCS group, unlike those in the control group, experienced reduced pain and improved health and quality of life after 6 months of treatment. In patients with refractory painful diabetic neuropathy, spinal cord stimulation therapy significantly reduced pain and improved quality of life.
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Randomized Controlled Trial
The effect of oxcarbazepine in peripheral neuropathic pain depends on pain phenotype: a randomised, double-blind, placebo-controlled phenotype-stratified study.
In neuropathic pain it has been suggested that pain phenotype based on putative pain mechanisms may predict response to treatment. This was a randomised, double-blind, placebo-controlled, and phenotype-stratified study with 2 6-week treatment periods of oxcarbazepine (1800-2400mg) and placebo. The primary efficacy measure was change in median pain intensity between baseline and the last week of treatment measured on an 11-point numeric rating scale, and the primary objective was to compare the effect of oxcarbazepine in patients with and without the irritable nociceptor phenotype as defined by hypersensitivity and preserved small nerve fibre function determined by detailed quantitative sensory testing. ⋯ In the total sample, oxcarbazepine relieved pain of 0.7 points (on a numeric rating scale 0-10; 95% confidence interval [CI] 0.4-1.4) more than placebo (P=0.015) and there was a significant interaction between treatment and phenotype of 0.7 (95% CI 0.01-1.4, P=0.047). The number needed to treat to obtain one patient with more than 50% pain relief was 6.9 (95% CI 4.2-22) in the total sample, 3.9 (95% CI 2.3-12) in the irritable, and 13 (95% CI 5.3-∞) in the nonirritable nociceptor phenotype. In conclusion, oxcarbazepine is more efficacious for relief of peripheral neuropathic pain in patients with the irritable vs the nonirritable nociceptor phenotype.
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Randomized Controlled Trial
Peripheral opioid receptor blockade increases postoperative morphine demands - a randomized, double-blind, placebo-controlled trial.
Experimental studies suggest that a large proportion of opioid analgesia can be mediated by peripheral opioid receptors. This trial examined the contribution of such receptors to clinical analgesia induced by intravenous morphine. We hypothesized that the selective blockade of peripheral opioid receptors by methylnaltrexone (MNX) would increase the patients' demand for morphine to achieve satisfactory postoperative pain relief. ⋯ Secondary endpoints were similar in all groups (P>.05). Thus, a significant proportion of analgesia produced by systemically administered morphine is mediated by peripheral opioid receptors. Drugs that selectively activate such receptors should have the potential to produce powerful clinical pain relief.
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Randomized Controlled Trial
A randomized, double-blind, placebo-controlled trial and open-label extension study to evaluate the efficacy and safety of pregabalin in the treatment of neuropathic pain associated with HIV neuropathy.
The objective of these studies was to assess the efficacy and safety of pregabalin in the treatment of human immunodeficiency virus (HIV)-associated neuropathic pain. Patients with HIV-associated distal sensory polyneuropathy (DSP) were randomized to treatment with flexible-dose pregabalin (150-600 mg/day) or placebo for 17 weeks in a single-blind, placebo lead-in, randomized, double-blind, parallel-group, placebo-controlled multinational trial. The primary efficacy outcome was the change in mean pain score on an 11-point numeric rating scale (NRS) from baseline to study endpoint. ⋯ Overall, this trial did not show pregabalin to be more efficacious than placebo in treating HIV-associated DSP. Studies such as these, which fail to support their primary hypotheses, may be important in informing the methodology of future trials, especially when novel approaches to limit variability in the control group are included. ClinicalTrials.gov identifiers: NCT01049217 and NCT01145417.
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Randomized Controlled Trial
tDCS modulates cortical nociceptive processing but has little to no impact on pain perception.
Transcranial direct current stimulation (tDCS) effectively modulates cortical excitability. Several studies suggest clinical efficacy in chronic pain syndromes. However, little is known regarding its effects on cortical pain processing. ⋯ However, contrasting the interaction of stimulation modes (anodal/cathodal) resulted in a significant decrease of activation in the hypothalamus, inferior parietal cortex, inferior parietal lobule, anterior insula, and precentral gyrus, contralateral to the stimulation site after anodal stimulation, which showed the opposite behavior after cathodal stimulation. Pain ratings and heat hyperalgesia showed only a subclinical pain reduction after anodal tDCS. Larger-scale clinical trials using higher tDCS intensities or longer durations are necessary to assess the neurophysiological effect and subsequently the therapeutic potential of tDCS.