Pain
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Randomized Controlled Trial
TRPV1 antagonist BCTC inhibits pH 6.0-induced pain in human skin.
Tissue acidosis due to ischemia occurs under several pathological conditions and is believed to contribute to pain in these circumstances. TRPV1, TRPA1, and ASICs are known to be sensitive to acidic pH. Addressing their possible role in acidosis perception, the respective antagonists BCTC, A-967079, and amiloride were injected in the volar forearm skin of 32 healthy volunteers. ⋯ Responses of hTRPV1 to acidic stimulation showed a maximum around pH6, providing an explanation for the pH-dependent inhibition by BCTC. A-967079 sensitizes pH responses is a TRPA1-responsive dorsal root ganglion neuron population, and a direct effect of A-967079 on hTRPA1 and hTRPV1 was excluded. In conclusion, inhibiting TRPV1-mediated acidosis-induced pain could be a symptomatic and potentially also a disease-modifying approach.
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Randomized Controlled Trial
A randomized placebo-controlled trial of desipramine, cognitive behavioral therapy, and active placebo therapy for low back pain.
This clinical trial evaluated the independent and combined effects of a tricyclic antidepressant (desipramine) and cognitive behavioral therapy (CBT) for chronic back pain relative to an active placebo treatment. Participants (n = 142) were patients experiencing daily chronic back pain at an intensity of ≥4/10 who were randomized to a single-center, double-blind, 12-week, 4-arm, parallel groups controlled clinical trial of (1) low concentration desipramine titrated to reach a serum concentration level of 15 to 65 ng/mL; (2) CBT and active placebo medication (benztropine mesylate, 0.125 mg); (3) low concentration desipramine and CBT; and (4) active benztropine placebo medication. Participants completed the Differential Description Scale and Roland Morris Disability Questionnaires before and after treatment as validated measures of outcomes in back pain intensity and disability, respectively. ⋯ However, intent-to-treat analyses at post-treatment showed no significant differences between any condition, with small effect sizes ranging from 0.06 to 0.27. The results from this clinical trial did not support the hypothesis that desipramine, CBT, or their combination would be statistically superior to an active medicine placebo for reducing chronic back pain intensity or disability. Key limitations included recruiting 71% of the planned sample size and use of multiple inclusion/exclusion criteria that may limit generalizability to broader populations of patients with chronic back pain.
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Randomized Controlled Trial
Intergroup anxiety in pain care: impact on treatment recommendations made by White providers for Black patients.
Race disparities in pain care are well-documented. Given that most black patients are treated by white providers, patient-provider racial discordance is one hypothesized contributor to these disparities. Research and theory suggest that providers' trait-level intergroup anxiety impacts their state-level comfort while treating patients, which, in turn, impacts their pain treatment decisions. ⋯ This study provides important new information about intrapersonal and interpersonal contributors to race disparities in chronic pain care. These findings suggest that intergroup anxiety and the resulting situational discomfort encroach on the clinical decision-making process by influencing white providers' decisions about which pain treatments to recommend to black patients. Should these findings be replicated in future studies, they would support interventions to help providers become more aware of their trait-level intergroup anxiety and manage their state-level reactions to patients who are racially/ethnically different from themselves.
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Randomized Controlled Trial Multicenter Study
Efficacy and safety of linaclotide for opioid-induced constipation in patients with chronic noncancer pain syndromes from a phase 2 randomized study.
Constipation is the most common adverse event (AE) of opioid therapy. This multicenter, phase 2 study evaluated the efficacy and safety of linaclotide in treating opioid-induced constipation (OIC) in patients with chronic noncancer pain syndromes (NCT02270983). Adults with OIC (<3 spontaneous bowel movements [SBMs]/week) related to chronic noncancer pain were randomized 1:1:1 to receive linaclotide 145 µg, linaclotide 290 µg, or placebo once daily for 8 weeks. ⋯ No serious AEs related to diarrhea were reported in any treatment group. Compared with placebo, linaclotide-treated patients had significant improvements in stool consistency, straining, abdominal bloating, and treatment satisfaction scores (P < 0.05). Linaclotide significantly improved OIC symptoms and was well tolerated in patients with chronic noncancer pain.
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Randomized Controlled Trial
New procedure of high-frequency repetitive transcranial magnetic stimulation for central neuropathic pain: a placebo-controlled randomized cross-over study.
Repetitive transcranial magnetic stimulation (rTMS) is a procedure increasingly used to treat patients with central neuropathic pain, but its efficacy is still under debate. Patients with medically refractory chronic central neuropathic pain were included in 2 randomized phases (active/sham), separated by a wash-out period of 8 weeks. Each phase consisted of 4 consecutive rTMS sessions and a final evaluation session, all separated from one another by 3 weeks. ⋯ No difference was observed for quality of life or analgesic drug consumption. Seventeen patients (47%) were identified as responders, but no significant interaction was found between clinical and technical factors considered here and the analgesic response. These results provide strong evidence that 3 weeks spaced high-frequency rTMS of M1 results in a sustained analgesic effect and support the clinical interest of this stimulation paradigm to treat refractory chronic pain.