The journal of pain : official journal of the American Pain Society
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Chronic vulvar pain is alarmingly common in women of reproductive age and is often accompanied by psychological distress, sexual dysfunction, and a significant reduction in quality of life. Localized provoked vulvodynia (LPV) is associated with intense vulvar pain concentrated in the vulvar vestibule (area surrounding vaginal opening). To date, the origins of vulvodynia are poorly understood, and treatment for LPV manages pain symptoms, but does not resolve the root causes of disease. ⋯ Inhibiting expression of one or both bradykinin receptors significantly reduces proinflammatory mediator production. Finally, we determined that bradykinin activates nuclear factor (NF)κB signaling (a major inflammatory pathway), whereas inhibition of NFκB successfully ablates this response. These data suggest that therapeutic agents targeting bradykinin sensing and/or NFκB may represent new, more specific options for LPV therapy.
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Opioid misuse, abuse, and overdose are a rapidly growing public health epidemic. Medicaid Lock-In Programs (MLIPs) are designed to prevent overutilization of controlled substances by Medicaid patients. However, despite widespread use, there is little information on their effect. ⋯ In our sample of 6,148 MLIP patients, the odds of having any opioid claim in a given month was 84% lower during MLIP enrollment relative to the period before enrollment (odds ratio = .16). MLIP enrollment also corresponded with a reduction in monthly number of opioid prescriptions by 1.13, monthly number of pharmacies by .61, and monthly Medicaid expenditures by $22.78. Although MLIPs may constitute a successful component of comprehensive efforts to reduce the potential overutilization of opioids, care should be taken to ensure that programs such as MLIPs do not constrain patients' legitimate needs for analgesic medications.
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Randomized Controlled Trial
Involvement of opioid receptors and α2-adrenoceptors in inhibitory pain modulation processes: a double-blind placebo-controlled crossover study.
In healthy humans, high-frequency electrical stimulation (HFS) of the forearm not only evokes local signs of central sensitization but also triggers broader ipsilateral inhibitory influences on pain akin to a lateralized form of conditioned pain modulation. Paradoxically, some of these inhibitory influences are augmented by α2-adrenoceptor blockade. To determine whether opioid peptides mediate inhibitory effects after HFS, the opioid receptor antagonist naltrexone was coadministered orally with the α2-adrenoceptor antagonist yohimbine in 16 healthy women in a double-blind placebo-controlled crossover study. ⋯ Unlike yohimbine alone, the naltrexone with yohimbine combination blocked analgesia evoked by HFS in the ipsilateral forehead to blunt pressure, and opposed the ipsilateral inhibitory effect of pain in the temple on electrically-evoked pain at the HFS-treated site in the forearm. These findings imply involvement of opioid peptides in an ipsilateral analgesic response that complements the more generalized form of conditioned pain modulation. Opioid mediation of this ipsilateral analgesic response appears to override opposing α2-adrenoceptor effects.
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Barriers to clinical trial recruitment can delay study completion, potentially resulting in increased costs and an unrepresentative sample. In the current study of 150 participants with chronic pain, we used a computerized adaptive choice-based conjoint survey that included 8 characteristics that may affect enrollment in pharmacologic pain treatment trials (ie, treatment allocation, frequency of pain ratings, treatment administration method, current medications, number of study visits, availability of evening and weekend visits, invasiveness of laboratory procedures, payment). ⋯ The fourth most important characteristic was number of study visits (13%), with participants preferring fewer in-person visits and more phone contacts. Understanding the preferences of potential participants is an important step toward enhancing enrollment in pain treatment trials.
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The current study examined the relationship between perceived injustice and attentional bias (AB) toward pain among individuals with chronic low back pain asked to perform and appraise the pain and difficulty of a standardized set of common physical activities. A pictorial dot-probe task assessed AB toward pain stimuli (ie, pain faces cueing pain), after which participants performed the physical tasks. Participants also rated face stimuli in terms of pain, sadness, and anger expression. ⋯ Exploratory analyses indicated that participants with higher levels of perceived injustice rated stimulus faces as sadder and angrier; no such differences emerged for pain ratings. To our knowledge, this is the first study to examine the association between perceived injustice and AB toward pain, as well as perceived injustice and in vivo appraisals of common physical activity. Results extend existing literature and suggest that attentional and potential interpretive bias should be considered in future research.