The journal of pain : official journal of the American Pain Society
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Randomized Controlled Trial
TRPA1 and TRPV1 antagonists do not inhibit human acidosis-induced pain.
Acidosis occurs in a variety of pathophysiological and painful conditions where it is thought to excite or contribute to excitation of nociceptive neurons. Despite potential clinical relevance the principal receptor for sensing acidosis is unclear, but several receptors have been proposed. We investigated the contribution of the acid-sensing ion channels, transient receptor potential vanilloid type 1 (TRPV1) and transient receptor potential ankyrin type 1 (TRPA1) to peripheral pain signaling. ⋯ A continuous intraepidermal injection of pH 4.3 was used to counter the buffering capacity of tissue and generate a prolonged painful stimulation. In this model, addition of A-967079, BCTC or amiloride did not reduce the reported pain. In conclusion, target-validated antagonists, applied locally in human skin, have excluded the main hypothesized targets and the mechanism of the human acidosis-induced pain remains unclear.
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Randomized Controlled Trial
Validity of Simplified Versus Standard Self-Report Measures of Pain Intensity in Preschool-Aged Children Undergoing Venipuncture.
There are inadequate age-specific data to support the use of current self-report pain scales in 3- and 4-year-old children. Most preschool-aged children also lack the necessary cognitive development to use standard scales. We aimed to evaluate the validity and feasibility of 2 novel simplified scales (Simplified Faces Pain Scale, S-FPS; Simplified Concrete Ordinal Scale, S-COS) for preschool-aged children. These simplified scales used a 2-step self-report method: children were first asked whether they have pain (yes/no); only if yes, then pain intensity was self-reported using a 3-point scale with visual aids signifying mild/moderate/severe. ⋯ Correlation with Face Legs Activity Cry Consolability was moderate to strong and cooperation rates were similar for all self-report scales. The simplified scales can improve and simplify pain assessment for 4-year-olds. Quantitative pain rating remains challenging for 3-year-olds.
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Randomized Controlled Trial
Prescription Opioid Taper Support for Outpatients with Chronic Pain: A Randomized Controlled Trial.
Patients receiving long-term opioid therapy for chronic pain and interested in tapering their opioid dose were randomly assigned to a 22-week taper support intervention (psychiatric consultation, opioid dose tapering, and 18 weekly meetings with a physician assistant to explore motivation for tapering and learn pain self-management skills) or usual care (N = 35). Assessments were conducted at baseline and 22 and 34 weeks after randomization. Using an intention to treat approach, we constructed linear regression models to compare groups at each follow-up. ⋯ Pain severity ratings (0-10 numeric rating scale) decreased in both groups at 22 weeks, with no significant difference between groups (adjusted mean difference = -.68; 95% confidence interval, -2.01 to .64; P = .30). The taper support group improved significantly more than the usual care group in self-reported pain interference, pain self-efficacy, and prescription opioid problems at 22 weeks (all P-values < .05). This taper support intervention is feasible and shows promise in reducing opioid dose while not increasing pain severity or interference.
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Randomized Controlled Trial Clinical Trial
Telehealth versus In-Person Acceptance and Commitment Therapy for Chronic Pain: A Randomized Non-Inferiority Trial.
The purpose of this randomized noninferiority trial was to compare video teleconferencing (VTC) versus in-person (IP) delivery of an 8-week acceptance and commitment therapy (ACT) intervention among veterans with chronic pain (N = 128) at post-treatment and at 6-month follow-up. The primary outcome was the pain interference subscale of the Brief Pain Inventory. Secondary outcomes included measures of pain severity, mental and physical health-related quality of life, pain acceptance, activity level, depression, pain-related anxiety, and sleep quality. ⋯ These findings generally suggest that ACT delivered via VTC can be as effective and acceptable as IP delivery for chronic pain. Future studies should examine the optimal delivery of ACT for patients with chronic pain who report low levels of activity. This trial was registered at ClinicalTrials.gov (NCT01055639).
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Randomized Controlled Trial Multicenter Study
Capsaicin 8% Patch in Painful Diabetic Peripheral Neuropathy: A Randomized, Double-Blind, Placebo-Controlled Study.
This 12-week study evaluated the efficacy and safety of capsaicin 8% patch versus placebo patch in painful diabetic peripheral neuropathy (PDPN). Patients aged 18 years or older with PDPN were randomized (1:1) to one 30-minute treatment (capsaicin 8% patch or placebo patch) to painful areas of the feet. Overall, 369 patients were randomized (capsaicin 8% patch, n = 186; placebo patch, n = 183). Percentage reduction in average daily pain score from baseline to between weeks 2 through 8 (the primary end point) was statistically significant for capsaicin 8% patch versus placebo (-27.4% vs -20.9%; P = .025); improvements in pain were observed from week 2 onward. Versus placebo, patients treated with capsaicin 8% patch had a shorter median time to treatment response (19 vs 72 days) and modest improvements in sleep interference scores from baseline to between weeks 2 through 8 (P = .030) and weeks 2 through 12 (P = .020). Apart from application site reactions, treatment-emergent adverse events were similar between groups. No indications of deterioration in sensory perception of sharp, cold, warm, or vibration stimuli were observed. In patients with PDPN, capsaicin 8% patch treatment provided modest pain relief and sleep quality improvements versus a placebo patch, similar in magnitude to other treatments with known efficacy, but without systemic side effects or sensory deterioration. ⋯ To our knowledge, this is the first study of the capsaicin 8% patch versus placebo in patients with PDPN to show that one 30-minute capsaicin treatment provides modest improvements in pain and sleep quality. Results confirm the clinical utility of the capsaicin 8% patch in the diabetic population.