Pain
-
Randomized Controlled Trial Multicenter Study
A multicenter randomized controlled trial on the efficacy of intradiscal methylene blue injection for chronic discogenic low back pain: the IMBI study.
A study published in PAIN in 2010 showed remarkable effects of intradiscal methylene blue (MB) injections compared with placebo on pain intensity in patients with chronic discogenic low back pain (CD-LBP). Both groups received lidocaine hydrochloride injections for pain associated with the procedure. We replicated the design of the previously published study and performed a multicenter, double-blind, randomized, placebo-controlled trial to assess whether the extraordinary effects of MB on pain intensity could be confirmed. ⋯ We were unable to confirm that intradiscal MB injections are better capable of significantly reducing pain in patients with CD-LBP 6 months after treatment compared with placebo. We observed that over one-quarter of patients receiving only lidocaine injections reported treatment success, which is in contrast with the previously published study. Our results do not support the recommendation of using intradiscal MB injections for patients with CD-LBP.
-
Randomized Controlled Trial
An experimental randomized study on the analgesic effects of pharmaceutical-grade cannabis in chronic pain patients with fibromyalgia.
In this experimental randomized placebo-controlled 4-way crossover trial, we explored the analgesic effects of inhaled pharmaceutical-grade cannabis in 20 chronic pain patients with fibromyalgia. We tested 4 different cannabis varieties with exact knowledge on their [INCREMENT]-tetrahydrocannabinol (THC) and cannabidiol (CBD) content: Bedrocan (22.4-mg THC, <1-mg CBD; Bedrocan International BV, Veendam, the Netherlands), Bediol (13.4-mg THC, 17.8-mg CBD; Bedrocan International BV, Veendam, the Netherlands), Bedrolite (18.4-mg CBD, <1-mg THC; Bedrocan International BV, Veendam, the Netherlands), and a placebo variety without any THC or CBD. After a single vapor inhalation, THC and CBD plasma concentrations, pressure and electrical pain thresholds, spontaneous pain scores, and drug high were measured for 3 hours. ⋯ Cannabidiol inhalation increased THC plasma concentrations but diminished THC-induced analgesic effects, indicative of synergistic pharmacokinetic but antagonistic pharmacodynamic interactions of THC and CBD. This experimental trial shows the complex behavior of inhaled cannabinoids in chronic pain patients with just small analgesic responses after a single inhalation. Further studies are needed to determine long-term treatment effects on spontaneous pain scores, THC-CBD interactions, and the role of psychotropic symptoms on pain relief.
-
Randomized Controlled Trial
Somatosensory profiles in acute herpes zoster and predictors of postherpetic neuralgia.
This prospective cohort study aimed to characterize the sensory profile during acute herpes zoster (AHZ) and to explore sensory signs as well as physical and psychosocial health as predictors for postherpetic neuralgia (PHN). Results of quantitative sensory testing of 74 patients with AHZ at the affected site and at the distant contralateral control site were compared to a healthy control group. Pain characteristics (Neuropathic Pain and Symptom Inventory and SES), physical functioning, and psychosocial health aspects (Pain Disability Index, SF-36, and STAI) were assessed by questionnaires. ⋯ Pain Disability Index (P = 0.036) and SES affective pain perception scores (P = 0.031) were over 50% higher, and 6 of 8 SF-36 subscores were over 50% lower (P < 0.045) in PHN. Sensory profiles in AHZ indicate deafferentation and central but not peripheral sensitization. Sensory signs at distant body sites, strong affective pain perception, as well as reduced quality of life and physical functioning in the acute phase may reflect risk factors for the transition to PHN.
-
Randomized Controlled Trial
Pain assessment in advanced dementia.Validity of the German Painad -a prospective double-blind randomised placebo-controlled trial.
Pain in combination with dementia is a common condition that makes pain recognition significantly more difficult. This results in undertreatment of pain in those suffering from dementia. The Pain Assessment in Advanced Dementia (PAINAD) scale currently represents one of the best approaches to pain detection in dementia. ⋯ Equally, none of the other 3 observational tools were able to demonstrate a significant difference between the study groups. However, correlations among the 4 observational tools were mostly moderate to high. A number of possible reasons for this observation, such as difficulties regarding sensitivity to change/responsiveness, consistence of the fundamental construct, influence of the early onset study, and efficacy of the analgesic in advanced dementia are discussed.
-
Randomized Controlled Trial
The association between endogenous opioid function and morphine responsiveness: a moderating role for endocannabinoids.
We sought to replicate previous findings that low endogenous opioid (EO) function predicts greater morphine analgesia and extended these findings by examining whether circulating endocannabinoids and related lipids moderate EO-related predictive effects. Individuals with chronic low-back pain (n = 46) provided blood samples for endocannabinoid analyses, then underwent separate identical laboratory sessions under 3 drug conditions: saline placebo, intravenous (i.v.) naloxone (opioid antagonist; 12-mg total), and i.v. morphine (0.09-mg/kg total). During each session, participants rated low-back pain intensity, evoked heat pain intensity, and nonpain subjective effects 4 times in sequence after incremental drug dosing. ⋯ In the absence of significant interactions, lower EO function predicted significantly greater morphine analgesia (as in past work) and euphoria. Results indicate that EO effects on analgesic and subjective responses to opioid medications are greatest when endocannabinoid levels are low. These findings may help guide development of mechanism-based predictors for personalized pain medicine algorithms.