European journal of pain : EJP
-
In patients with pain of malignant origin morphine may be administered in high and often increasing doses during extended periods of time. In patients with chronic pain of non-malignant origin morphine may be an important remedy, and in these cases the goal is to keep the morphine dose stable. The pharmacokinetic as well as the pharmacodynamic consequences of long-term morphine treatment with special reference to the two most important metabolites of morphine morphine-6-glucuronide (M-6-G) and morphine-3-glucuronide (M-3-G) remain to be settled. ⋯ In the cancer patient group neither dose nor treatment period seems to influence morphine glucuronidation. Likewise in the non-cancer patient group receiving stable doses of morphine duration of treatment does not seem to influence morphine glucuronidation. Dryness of the mouth was positively correlated to high plasma concentrations of morphine and M-6-G.
-
Randomized Controlled Trial Clinical Trial
Impaired disengagement from threatening cues of impending pain in a crossmodal cueing paradigm.
This paper reports an experimental investigation of attentional engagement to and disengagement from cues of impending pain. Pain-free volunteers performed a cueing task in which they were instructed to detect somatosensory and tone targets. Target stimuli were preceded by visual cues informing participants of the modality of the impending stimuli. ⋯ Analyses revealed a similar amount of attentional engagement to both cues signalling somatosensory targets, irrespective of their threat value. However, participants had significantly more difficulty in disengaging attention from a threatening cue of impending pain compared to a cue signalling the non-painful vibrotactile target. Our findings provide further evidence that pain cues demand attention, particularly resulting in impaired disengagement.
-
Clinical Trial Controlled Clinical Trial
Peripheral effects of needle stimulation (acupuncture) on skin and muscle blood flow in fibromyalgia.
Acupuncture has become a widely used treatment modality in various musculoskeletal pain conditions. Acupuncture is also shown to enhance blood flow and recovery in surgical flaps. The mechanisms behind the effect on blood flow were suggested to rely on vasoactive substances, such as calcitonin gene-related peptide, released from nociceptors by the needle stimulation. ⋯ The results of the present study were partly similar to those earlier found at a corresponding site in healthy female subjects, i.e., deep muscle stimulation resulted in larger increase in skin blood flow (mean (SE)): 62.4% (13.0) and muscle blood flow: 93.1% (18.6), compared to baseline, than did subcutaneous insertion (mean (SE) skin blood flow increase: 26.4% (6.2); muscle blood flow increase: 46.1% (10.2)). However, in FM patients subcutaneous needle insertion was followed by a significant increase in both skin and muscle blood flow, in contrast to findings in healthy subjects where no significant blood flow increase was found following the subcutaneous needling. The different results of subcutaneous needling between the groups (skin blood flow: p=0.008; muscle blood flow: p=0.027) may be related to a greater sensitivity to pain and other somatosensory input in FM.
-
Cutting spinal nerves just distal to the dorsal root ganglion (DRG) triggers, with rapid onset, massive spontaneous ectopic discharge in axotomized afferent A-neurons, and at the same time induces tactile allodynia in the partially denervated hindlimb. We show that secondary transection of the dorsal root (rhizotomy) of the axotomized DRG, or suppression of the ectopia with topically applied local anesthetics, eliminates or attenuates the allodynia. ⋯ These observations support the hypothesis that ectopic firing in DRG A-neurons induces central sensitization which leads to tactile allodynia. The question of how activity in afferent A-neurons, which are not normally nociceptive, might induce allodynia is discussed in light of the current literature.
-
The usefulness of the verbal pain rating scale (VRS) included in the Short Form 36 (SF-36) in identifying characteristics of long-term pain conditions, was analyzed using data from the 1994 Danish Health and Morbidity Survey. Based on the rating of pain intensity during a 4-week recall period the respondents were categorized into three groups: a high pain group (HPG) consisting of persons reporting moderate to severe pain (VRS 4-6), a low pain group (LPG) who rated their pain as very mild or mild (VRS 2-3), and a control group (CG) with no pain (VRS 1). The investigated sample comprised 3992 persons (HPG=563 persons, LPG=1714, and CG=1715 persons). ⋯ Mean numbers of in-hospital days were 1.60, 0.80, and 0.43 for the HPG, LPG, and CG, respectively. Our study suggest that one-dimensional pain intensity scoring using a simple VRS-scoring is useful as a screening instrument for identifying persons suffering from pain of a more complex nature. High intensity scores on a pain intensity scale should indicate to the investigator that she/he might be facing a person whose pain complaints and behavior are not only based on a pure biological background, but in whom also severe psychological and social problems might be present.