The journal of pain : official journal of the American Pain Society
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Prescription opioid abuse and diversion are major causes of morbidity and mortality in the United States. The buprenorphine transdermal delivery system (BTDS) is indicated for the treatment of moderate to severe chronic pain and provides a continuous dose of 5, 7.5, 10, 15, or 20 μg/h buprenorphine for 7 days. Quarterly rates of abuse and diversion of BTDS were compared with 4 comparator groups: 1) other buprenorphine products, 2) fentanyl patches, 3) extended-release (ER) opioid tablets/capsules, and 4) ER tramadol. Data were obtained from the Researched Abuse, Diversion and Addiction-Related Surveillance (RADARS) System Poison Center, Drug Diversion, Treatment Programs Combined (Opioid Treatment and Survey of Key Informants' Patients Programs), and College Survey Programs. Rates were calculated using case counts per population and mentions per prescriptions filled. Poisson regression analysis was used to compare mean rates over time across drug groups after allowing for drug group-specific dispersion parameters. Population adjusted abuse rates were low for BTDS in all of the RADARS System programs compared with the other comparator groups. Findings were similar for the prescription adjusted rates, with BTDS reported at the lowest rates in all programs. Route of abuse differed slightly for BTDS and the comparator groups depending on the program. BTDS was abused and diverted at low rates compared with the other opioid groups in 5 programs of the RADARS System using either population-based rates or prescription dispensed rates. ⋯ Data from the RADARS System show the BTDS is abused and diverted at low rates compared with other opioid groups including other forms of buprenorphine, fentanyl patches, ER opioid formulations, and ER tramadol.
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The Pain Self-Efficacy Questionnaire (PSEQ) is a valid and reliable patient-reported instrument used to assess pain self-efficacy in patients with chronic low back pain (CLBP). Recently, the 2-item (PSEQ-2) and the 4-item (PSEQ-4) short versions were developed showing satisfactory measurement properties in mixed populations with chronic pain. The aim of this study was to examine responsiveness and minimal important change (MIC) of PSEQ, PSEQ-2, and PSEQ-4 in patients with CLBP. We used a sample of 104 patients undergoing multimodal physical therapy designed to partly change pain self-efficacy beliefs. Responsiveness was assessed by testing 16 a priori formulated hypotheses regarding effect sizes, areas under the curve, and correlations with changes in other instruments measuring other constructs. The MIC was calculated using an external anchor specific for pain self-efficacy and the receiver operator characteristic (ROC) method. The PSEQ and the PSEQ-4 met all hypotheses, whereas the PSEQ-2 met all but 1. The MICs were 5.5 for the PSEQ (9% of the scale range) and 1.5 for PSEQ-2 (13% scale range) and PSEQ-4 (6% scale range). MIC values were different for patients with low or high baseline values for all 3 instruments. The PSEQ and its short versions are adequately responsive instruments in patients with CLBP. ⋯ This study suggests that the PSEQ and its short versions are responsive measures of pain self-efficacy in patients with CLBP, adding to previous literature on their validity and reliability. Considering their similar responsiveness, the 4-item PSEQ could replace the original 10-item version in busy clinical or research settings.
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Aconitine and its structurally-related diterpenoid alkaloids have been shown to interact differentially with neuronal voltage-dependent sodium channels, which was suggested to be responsible for their analgesia and toxicity. Bulleyaconitine A (BAA) is an aconitine analogue and has been prescribed for the management of pain. The present study aimed to evaluate the inhibitory effects of BAA on pain hypersensitivity and morphine antinociceptive tolerance, and explore whether the expression of dynorphin A in spinal microglia was responsible for its actions. Single intrathecal or subcutaneous (but not intraventricular or local) injection of BAA blocked spinal nerve ligation-induced painful neuropathy, bone cancer-induced pain, and formalin-induced tonic pain by 60 to 100% with the median effective dose values of 94 to 126 ng per rat (intrathecal) and 42 to 59 μg/kg (subcutaneous), respectively. After chronic treatment, BAA did not induce either self-tolerance to antinociception or cross-tolerance to morphine antinociception, and completely inhibited morphine tolerance. The microglial inhibitor minocycline entirely blocked spinal BAA (but not exogenous dynorphin A) antinociception, but failed to attenuate spinal BAA neurotoxicity. In a minocycline-sensitive and lidocaine- or ropivacaine-insensitive manner, BAA stimulated the expression of dynorphin A in the spinal cord, and primary cultures of microglia but not of neurons or astrocytes. The blockade effects of BAA on nociception and morphine tolerance were totally eliminated by the specific dynorphin A antiserum and/or κ-opioid receptor antagonist. Our results suggest that BAA eliminates pain hypersensitivity and morphine tolerance through directly stimulating dynorphin A expression in spinal microglia, which is not dependent on the interactions with sodium channels. ⋯ The newly illustrated mechanisms underlying BAA antinociception help us to better understand and develop novel dynorphin A expression-based painkillers to treat chronic pain.
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Evidence from a number of sources supports the existence of two relatively independent neurophysiological systems that underlie avoidance- and approach-related emotions, cognitions, and behavior. There is considerable overlap between 1) the emotions, cognitions, and behaviors controlled by these two systems, and 2) the known effects of chronic pain. Here we propose a 2-factor model of chronic pain on the basis of these well established 2-factor models, and discuss the implications of the model for understanding the effects of pain and mechanisms of psychological pain treatments. The model makes specific hypotheses, which are unique to the proposed model, regarding the mechanisms underlying pain's negative influence and the benefits of psychological pain treatments. The model also provides an overarching framework that could enhance outcomes by 1) broadening the assessment of factors that may be influencing pain and its effect on individual patients, and 2) suggesting that specific techniques from different treatments may be combined to better target these factors. ⋯ The 2-factor model presented in this report provides a framework for understanding the effects of psychological pain treatments, and makes specific a priori hypotheses regarding the specific mechanisms of those treatments. Clinical applications of the model have the potential for enhancing treatment outcomes.