The journal of pain : official journal of the American Pain Society
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Our goal was to assess the patient-level burden among subjects with painful diabetic peripheral neuropathy (DPN). Community-based physicians recruited patients with painful DPN (N = 255) between April and October 2003. Patients completed a survey on pain experience (Brief Pain Inventory-DPN [BPI-DPN]), health status (EuroQoL [EQ-5D]), healthcare utilization (consults, prescription [Rx], and over-the-counter [OTC] medications), and work productivity/functioning. Patients were 61 +/- 12.8 years old and had diabetes for 12 +/- 10.3 years and painful DPN for 6.4 +/- 6.4 years; 25.5 and 62.7% had other neuropathic and musculoskeletal pain conditions. Average and worst pain scores (BPI-DPN, 0-10 scales) were 5.0 +/- 2.5 and 5.6 +/- 2.8. The mean EQ-5D utility was .5 +/- .3 (range = -.594-1). A majority (87.4%) took pain medications (Rx/OTC) in the preceding week: an average of 3.8 +/- 3.9 Rx and 2.1 +/- 1.3 OTC medications. Nearly half (46.7%) received NSAIDs. Other frequently reported medications were short/long-acting opioids (43.1%), anticonvulsants (27.1%), selective serotonin reuptake inhibitors/selective norepinephrine reuptake inhibitors (18%), and tricyclic antidepressants (11.4%). During the preceding 3 months, 59.6% had >or=2 health professional consults; 59% reported decreased home productivity; 85.5% reported activity limitations; and 64.4% of patients who worked (N = 73) reported missing work/decreased work productivity due to painful DPN. Our results underscore a substantial patient-level burden among subjects with painful DPN. ⋯ Information on the patient-level burden among painful DPN sufferers in the U.S. was previously lacking. Our results suggest that this burden is significant, evidenced by moderate-to-high pain levels, polypharmacy, health resource use, and work/activity limitations. Results also suggest suboptimal pain management and low levels of satisfaction with treatments.
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Comparative Study
DHEAS deficiency during consumption of sustained-action prescribed opioids: evidence for opioid-induced inhibition of adrenal androgen production.
Dehydroepandrosterone (DHEA)-dehydroepiandrosterone sulfate (DHEAS) deficiency often produces fatigue, depression, weakness, and sexual dysfunction, which improve during replacement therapy. DHEAS deficiency is a sensitive marker for generalized adrenal insufficiency, but it has not been related to opioid ingestion. DHEAS values were determined in 34 male and 32 female opioid-consuming outpatients aged 35-78 years, in stable health, and in 33 male and 53 female nonopioid-consuming control subjects. No subjects used anticonvulsants or corticosteriod medications, and none had malignant, collagen-vascular, or endocrine disease other than menopause or opioid-induced androgen deficiency. Adrenocorticotropic hormone (ACTH) values were measured in 94 of 152 subjects. DHEAS levels were lower in opioid consumers than in control subjects in a dose-related pattern (P < .01), were below age-specific norms in 67% of opioid consumers and 8% of controls (P < .001), and were below our laboratory's lowest detection limit (15 mug/dL) in 29% of opioid users and 1% of controls (P < .001). DHEAS values were also lower in opioid-consuming nonsmokers than in smokers (P < .05) and were unrelated to body mass index or concurrent hormonal replacement therapy. ACTH levels were normal and unrelated to opioid use. The combination of subnormal DHEAS levels in the presence of normal ACTH values in most opioid-consuming patients suggests that these low levels result from factors other than diminished adrenal ACTH stimulation. ⋯ The study documents a dose-related DHEAS deficiency in a majority of nonhospitalized adults who are chronically consuming sustained-action oral or transdermal opioids for control of nonmalignant pain. This deficiency in these patients has not previously been recognized and is probably symptomatic. Evaluation of replacement therapy should receive high priority.
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The aim of this study was to further validate our carrageenan-induced temporomandibular joint (TMJ) inflammatory hyperalgesia model in rats by showing that administration of indomethacin before the initiation of inflammation would diminish the TMJ hyperalgesia. Using this model, we investigated whether norepinephrine and local beta-adrenoceptors contribute to the development of inflammatory TMJ hyperalgesia. Carrageenan-induced TMJ hyperalgesia was assessed by measuring the behavioral nociceptive responses, such as rubbing the orofacial region and flinching the head, induced by the injection of a low dose of 5-hydroxytryptamine into the TMJ sensitized 1 h before by a TMJ injection of carrageenan. Blockade of prostaglandin synthesis by indomethacin prior to initiation of inflammation by carrageenan significantly attenuated the TMJ hyperalgesia. The guanethidine depletion of norepinephrine or the blockade of beta(2)but not the blockade of the beta(1)-adrenoceptor by the selective adrenoceptor antagonists ICI 118.55 and atenolol, respectively, significantly reduced carrageenan-induced TMJ hyperalgesia. In the present study, we further validated our carrageenan-induced TMJ hyperalgesia model to study the mechanisms involved in inflammatory TMJ hyperalgesia and to test the analgesic effect of different types of peripheral analgesics. We also demonstrated that norepinephrine released at the site of injury contributes to the development of the inflammatory TMJ hyperalgesia by the activation of beta(2)-adrenoceptors. ⋯ The findings that local sympathomimetic amines contribute to the inflammatory TMJ hyperalgesia by activating beta(2)-adrenoceptors may be relevant to clinical TMJ inflammatory pain states less sensitive to nonsteroidal anti-inflammatory drugs.
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Randomized Controlled Trial Multicenter Study Comparative Study
Oxytrex minimizes physical dependence while providing effective analgesia: a randomized controlled trial in low back pain.
Physical dependence or withdrawal is an expected effect of prolonged opioid therapy. Oxytrex (oxycodone + ultralow-dose naltrexone) is an investigational drug shown here to minimize physical dependence while providing strong analgesia with twice-daily dosing. In this 719-patient, double-blind, placebo- and active-controlled Phase III clinical trial in chronic low back pain, patients were randomized to receive placebo, oxycodone qid, or oxytrex qid or bid. Each oxytrex tablet contains 1 microg naltrexone; oxytrex bid and qid treatments provide 2 and 4 microg naltrexone/day, respectively. Following a washout, patients with pain >or=5 on a 0-10 scale were dose-escalated weekly from 10 up to 80 mg/day until reaching adequate pain relief (
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The aim of the current study was to adapt the orofacial formalin pain model previously developed in rats for use in mice and to characterize as fully as possible the behavioral changes in this species. The effects of subcutaneous injection of different formalin concentrations (.5%, 1%, 2%, 4%, and 8%) were examined on the face-rubbing response. In mice, formalin injection into the upper lip induced sustained face-rubbing episodes with vigorous face-wash strokes directed to the perinasal area. A positive linear relationship between formalin concentration and amplitude of the rubbing activity was observed during the first and second phase of the test with concentration up to 4%. With the highest concentration used (8%), the amplitude of both phases had plateaued. Systemic administration of morphine and paracetamol induced a dose-dependent inhibition of the rubbing behavior during the second phase. Although both paracetamol and morphine inhibited the first phase, a dose-dependent inhibition was found only for morphine. The ED50 value (95% confidence interval) for suppressing the rubbing response during the first phase was 2.45 mg/kg (1.90-3.08 mg/kg) for morphine. The ED50 values for suppressing the rubbing response during the second phase were 3.52 mg/kg (2.85-4.63 mg/kg) for morphine and 100.66 mg/kg (77.98-139.05 mg/kg) for paracetamol. Heterosegmental nociceptive stimulation evoked by subcutaneous injection of capsaicin into the back of the animal 10 min before the formalin test produced a dose-dependent inhibition of the second phase of the rubbing response. The ED50 values for suppressing the rubbing response during the first and second phases were 9.04 microg (1.36-65.13 microg) and 0.92 microg (0.28-2.99 microg), respectively. In conclusion, the mouse orofacial formalin test appears to be a reliable model for studying the behavioral encoding of the intensity of nociceptive orofacial stimulation and the counter-irritation phenomenon and for testing analgesic drugs. ⋯ To further exploit the new opportunities of investigating nociceptive processing at the molecular level with the transgenic "knockout" approach, we require suitable behavioral models in mice. The presented mouse orofacial formalin test appears to be a reliable model for studying the behavioral encoding of the intensity of nociceptive stimulation and the counter-irritation phenomenon and for testing analgesic drugs.