Pain
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Randomized Controlled Trial
A randomized, double-blind, placebo-controlled study of daily cannabidiol for the treatment of canine osteoarthritis pain.
Over the last 2 decades, affirmative diagnoses of osteoarthritis (OA) in the United States have tripled due to increasing rates of obesity and an aging population. Hemp-derived cannabidiol (CBD) is the major nontetrahydrocannabinol component of cannabis and has been promoted as a potential treatment for a wide variety of disparate inflammatory conditions. Here, we evaluated CBD for its ability to modulate the production of proinflammatory cytokines in vitro and in murine models of induced inflammation and further validated the ability of a liposomal formulation to increase bioavailability in mice and in humans. ⋯ Liposomal CBD (20 mg/day) was as effective as the highest dose of nonliposomal CBD (50 mg/day) in improving clinical outcomes. Hematocrit, comprehensive metabolic profile, and clinical chemistry indicated no significant detrimental impact of CBD administration over the 4-week analysis period. This study supports the safety and therapeutic potential of hemp-derived CBD for relieving arthritic pain and suggests follow-up investigations in humans are warranted.
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Sleep disruption caused by obstructive sleep apnea (OSA) may be associated with hyperalgesia and may contribute to poor pain control and use of prescription opioids. However, the relationship between OSA and opioid prescription is not well described. We examine this association using cross-sectional data from a national cohort of veterans from recent wars enrolled from October 1, 2001 to October 7, 2014. ⋯ Further dividing opioid categories by high vs low dosage did not yield substantially different results. Obstructive sleep apnea is associated with a two-fold likelihood of being prescribed opioids for pain. Clinicians should consider incorporating OSA treatment into multimodal pain management strategies; OSA as a target for pain management should be further studied.
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Pain is a severe and common symptom in patients receiving dialysis but remains inadequately managed in clinical practice. Understanding patient experiences of pain can inform strategies to address this patient-important symptom. We aimed to describe patients' perspectives on causes, experiences, and impacts of dialysis-associated pain. ⋯ Struggling with pain in dialysis involved a progression of agony, fear, avoidance, and despair. However, support from others and self-management strategies were used to cope with pain. Strategies to empower patients to report and minimize pain and its consequences in dialysis are needed.
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Pharmacological tools for chronic visceral pain management are still limited and inadequate. A3 adenosine receptor (A3AR) agonists are effective in different models of persistent pain. Recently, their activity has been related to the block of N-type voltage-gated Ca2+ channels (Cav2.2) in dorsal root ganglia (DRG) neurons. ⋯ Furthermore, patch-clamp recordings showed that A3AR agonists inhibited Cav2.2 in dorsal root ganglia neurons isolated from either control or DNBS-treated rats. The effect on Ca2+ current was PD173212-sensitive and prevented by MRS1523. A3AR agonists are effective in relieving visceral hypersensitivity induced by DNBS, suggesting a potential therapeutic role against abdominal pain.
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High-threshold mechanosensitive and mechanoinsensitive ("silent") nociceptors have similar electrical thresholds for transcutaneous sine wave stimulation at 4 Hz that selectively activates cutaneous C nociceptors in human skin. Their fundamentally different functions particularly in chronic pain warrant differential stimulation protocols. We used transcutaneously delivered slow depolarizing stimuli (half-sine, 500 ms duration, 0.01-1 mA) in humans to assess intensity-response relations for the induction of pain psychophysically and recorded activation of mechanosensitive and silent nociceptors in healthy volunteers by microneurography. ⋯ In pig skin, the amplitude-dependent activation of mechanosensitive nociceptors was confirmed (0.2-1 mA, n = 28), and activation thresholds for most silent nociceptors (n = 13) were found above 10 mA. Non-nociceptive low-threshold mechanosensitive C fibers (n = 14) displayed lower activation thresholds for half-sine wave stimuli with an amplitude-dependent discharge increase between 0.01 and 0.1 mA. We conclude that transcutaneous electrical stimulation with 500-ms half-sine wave pulses between 0.2 and 1 mA causes amplitude-dependent pain by preferential activation of mechanosensitive C nociceptors.