The journal of pain : official journal of the American Pain Society
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Randomized Controlled Trial
Analgesic efficacy and safety of oxycodone in combination with naloxone as prolonged release tablets in patients with moderate to severe chronic pain.
This randomized, double-blind, placebo- and active-controlled, parallel-group study was designed to demonstrate the superiority of oxycodone in combination with naloxone in a prolonged release (PR) formulation over placebo with respect to analgesic efficacy. The active control group was included for sensitivity and safety analyses, and furthermore to compare the analgesic efficacy and bowel function of oxycodone PR/naloxone PR with oxycodone PR alone. The analgesic efficacy was measured as the time from the initial dose of study medication to multiple pain events (ie, inadequate analgesia) in patients with moderate to severe chronic low back pain. The full analysis population consisted of 463 patients. The times to recurrent pain events were significantly longer in the oxycodone PR/naloxone PR group compared with placebo (P < .0001-.0003); oxycodone PR/naloxone PR reduced the risk of pain events by 42% (P < .0001; full analysis population). The appearance of pain events was comparable for oxycodone PR/naloxone PR versus oxycodone PR, confirming that the addition of naloxone PR to oxycodone PR in a combination tablet did not negatively affect analgesic efficacy of the opioid. Furthermore, oxycodone PR/naloxone PR offers benefits in terms of an improvement in bowel function. In a therapeutic area of great unmet need, therefore, the combination tablet of oxycodone PR/naloxone PR offers patients effective analgesia while improving opioid-induced bowel dysfunction. Taken together with the observation that the safety profile of oxycodone PR/naloxone PR is consistent with that expected from other opioid analgesics except opioid-induced constipation, these findings indicate that the addition of naloxone to oxycodone in a PR combination tablet offers improved tolerability. Oxycodone PR/naloxone PR is therefore a promising new treatment approach for the management of chronic pain. ⋯ This study evaluated the analgesic efficacy and safety of the combination of oxycodone PR/naloxone PR in chronic nonmalignant pain. Opioids are often reduced in dosage or even discontinued as a result of impaired bowel function, leading to insufficient pain treatment. Not only does oxycodone PR/naloxone PR demonstrate analgesic efficacy comparable with oxycodone PR, but it also improves opioid-induced bowel dysfunction, and may therefore improve the acceptability of long-term opioid treatment for chronic pain.
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Multicenter Study
Validating PRISM (Pictorial Representation of Illness and Self Measure) as a measure of suffering in chronic non-cancer pain patients.
The Pictorial Representation of Illness and Self Measure (PRISM) is a recently developed tool designed to measure the burden of suffering due to illness in a variety of patient populations. The purpose of the current study was to validate PRISM as a measure of suffering in patients with chronic non-cancer pain. Patients (n = 138) were recruited from 2 hospital pain clinics, where they were participating in a 10-week, mindfulness-based chronic pain management course and during which they completed validated questionnaires to assess their outcomes. Convergent validity was assessed by correlating their PRISM scores with scores on the Short-Form 36v2 quality of life instrument, the Pain Catastrophizing Scale, and the 0 to 10 Numeric Pain Scale. Content validity and test-retest reliability were assessed, and a factor analysis performed to identify relationships among the PRISM domains. PRISM was found to have good reliability and was significantly correlated with many of the subdomains of the other questionnaires. Qualitative data (n = 26) revealed that PRISM was well understood and that there was consistency in interpreting the task. Our data suggest that the PRISM task measures constructs relating to quality of life, pain catastrophizing, and pain intensity and probably measures suffering in patients with chronic non-cancer pain, providing a novel and quick tool for clinicians. ⋯ This study demonstrates the reliability and validity of the PRISM task for measuring the burden of pain in a population of chronic pain sufferers. Clinicians in the field of chronic pain management may find PRISM useful for monitoring the impact of pain management strategies on pain perception and the psychosocial variables that influence suffering.
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Randomized Controlled Trial
Reduction of pain-related fear and disability in post-traumatic neck pain: a replicated single-case experimental study of exposure in vivo.
For patients with acute post-traumatic neck pain (PTNP), pain-related fear has been identified as a potential predictor of chronic disability. If such is the case, fear reduction should enhance the prevention of further pain disability and distress after traumatic neck pain disability. However, exposure-based treatments have not been tested in patients with PTNP. Using a replicated single-case crossover phase design with multiple measurements, this study examined whether the validity of a graded exposure in vivo, as compared with usual graded activity, extends to PTNP. Eight patients who reported substantial pain-related fear were included in the study. Daily changes in pain intensity, pain-related fear, pain catastrophizing, and activity goal achievement were assessed. Before and after each intervention, and at 6-month follow-up, standardized questionnaires of pain-related fear and pain disability were administered, and, to quantify daily physical activity level, patients carried an ambulatory activity monitor. The results showed decreasing levels of self-reported pain-related fear, pain intensity, disability, and improvements in physical activity level only when graded exposure in vivo was introduced, and not in the graded activity condition. The results are discussed in the context of the search for customized treatments for PTNP. ⋯ This is the first study showing that the effects of graded exposure in vivo generalize to patients with chronic PTNP reporting elevated levels of pain-related fear. This could help clinicians to customize treatments for PTNP.
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Clinical Trial
A study of clinical, magnetic resonance imaging, and somatosensory-evoked potential in central post-stroke pain.
This study evaluates the clinical spectrum of central post-stroke pain (CPSP) and correlates it with magnetic resonance imaging (MRI) and somatosensory-evoked potential (SEP) changes. Thirty-one consecutive CPSP patients whose median age was 51 years were evaluated and subjected to quantitative sensory testing and median and tibial SEPs. Cranial MRI abnormalities were noted and correlated with clinical and SEP abnormalities. The majority of patients (n = 21) developed CPSP within 3 months of stroke, and CPSP was the presenting symptom in 7 patients. Five patients had focal symptoms and 26 had hemibody symptoms with or without facial involvement. Pain threshold was reduced in 12, and 3 did not have pain perception. Allodynia was present in 11, static in 4, dynamic in 5, and cold in 7 patients. Temporal summation was present in 14, punctate hyperalgesia in 11, and cold hyperalgesia in 3 patients. Cranial MRI revealed infarction in 23 and intracerebral hemorrhage in 8 patients; 16 had thalamic and 15 extrathalamic lesions. SEP was abnormal in 15 of 22 (68.2%) patients. There was no difference in symptoms and severity of CPSP, quantitative sensory testing, and SEP abnormalities in thalamic and extrathalamic stroke. ⋯ CPSP is a poorly recognized entity that can interfere with rehabilitation, reduce the quality of life, and interfere with the activities of daily living and recreational activities. This report concludes that the symptoms and severity of CPSP in thalamic and extrathalamic stroke do not differ significantly.