Pain
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Dysmenorrhea is a common chronic pelvic pain syndrome affecting women of childbearing potential. Family studies suggest that genetic background influences the severity of dysmenorrhea, but genetic predisposition and molecular mechanisms underlying dysmenorrhea are not understood. In this study, we conduct the first genome-wide association study to identify genetic factors associated with dysmenorrhea pain severity. ⋯ Participants reporting extreme dysmenorrhea pain were more likely to report being positive for endometriosis, polycystic ovarian syndrome, depression, and other psychiatric disorders. Our results indicate that dysmenorrhea pain severity is partly genetically determined. NGF already has an established role in chronic pain disorders, and our findings suggest that NGF may be an important mediator for gynaecological/pelvic pain in the viscera.
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We linked UK cancer registry data with the corresponding electronic primary care medical records of 6080 patients who died of cancer over a 7-year period in a large United Kingdom city. We extracted all prescriptions for analgesics issued to each patient in the linked cohort during the 12 months before death and analysed the extent and duration of strong opioid treatment with clinical and patient characteristics. Strong opioids were prescribed for 48% of patients in the last year of life. ⋯ The study provides the first detailed analysis of the relatively late onset and short duration of strong opioid treatment in patients with cancer before death in a representative UK cohort. This pattern of prescribing does not match epidemiological data which point to earlier onset of pain. Although persistent undertreatment of cancer pain is well documented, this study suggests that strategies for earlier pain assessment and initiation of strong opioid treatment in community-based patients with cancer could help to improve pain outcomes.
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Studies have suggested that alcohol consumption is strongly related to reduced reporting of chronic widespread pain (CWP) and level of disability in people with CWP or fibromyalgia. Direction of causality has not been established, that is whether the association is due to people's health influencing their alcohol consumption or vice versa. UK Biobank recruited over 500,000 people aged 40 to 69 years, registered at medical practices nationwide. ⋯ In males who reported drinking the same as 10 years previously, there was a U-shaped relationship between amount drunk and odds of reporting CWP (nondrinkers CWP prevalence 2.4%, 19.1-32.1 units/wk 0.4%, >53.6 units/wk 1.0%; adjORs 2.53 95% confidence intervals [1.78-3.60] vs 1 vs 1.52 [1.05-2.20]). In females, there was a decrease in the proportion reporting CWP up to the modal category of alcohol consumption with no further change in those drinking more (nondrinkers CWP prevalence 3.4%, 6.4-11.2 units/wk 0.7%, >32.1 units/wk 0.7%; adjORs 2.11 [1.67-2.66] vs 1 vs 0.86 [0.54-1.39]). This large study has shown a clear relationship between alcohol consumption and reporting of pain even in people who had not reported changing consumption because of health concerns, after adjustment for potential confounding factors.
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The organic cation transporter OCT1 (SLC22A1) mediates uptake and metabolism of the active tramadol metabolite (+)O-desmethyltramadol in the liver. In this study, the influence of OCT1 genetic polymorphisms on pharmacokinetics and analgesic efficacy of tramadol in patients recovering from surgery was analyzed in addition to the CYP2D6 genotype. Postoperative patients who received tramadol through patient-controlled analgesia were enrolled. ⋯ Plasma areas under the concentration-time curves of (+)O-desmethyltramadol were 111.8 (95% confidence interval: 63.4-160.1), 80.2 (65.1-95.3), and 64.5 (51.9-77.2) h·ng·mL in carriers of 0, 1, or 2 active OCT1 alleles (P = 0.03). Loss of OCT1 function resulted in reduced tramadol consumption and increased plasma concentrations of (+)O-desmethyltramadol in patients recovering from surgery. Therefore, analyzing OCT1 next to CYP2D6 genotype might further improve future genotype-dependent dose recommendations for tramadol.
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Itch is a major indicator of psoriasis, but the underlying mechanisms behind this symptom are largely unknown. To investigate the neuronal mechanisms of psoriatic itch, we tested whether mice subjected to the imiquimod-induced psoriasis model exhibit itch-associated behaviors. Mice received daily topical applications of imiquimod to the rostral back skin for 7 days. ⋯ Neither chlorpheniramine nor olopatadine affected alloknesis on day 2 or day 7. These results may reflect the limited antipruritic effects of histamine H1-receptor antagonists on human psoriasis. The imiquimod-induced psoriasis model seems to be useful for the investigation of itch and its sensitization in psoriasis.