The Clinical journal of pain
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Randomized Controlled Trial
Mirtazapine decreases the pain feeling in healthy participants.
The treatment of neuropathic pain is mainly based on antiepileptics, tricyclic antidepressants, and opiates. These drugs have important side effects disturbing the patient's quality of life. Mirtazapine (MTZ) is a new and well-tolerated tricyclic antidepressants with both monoaminergic and opioid properties that might favorably influence pain. The aim of this study was to assess whether MTZ can reduce the pain induced by a standardized stimulus presented to healthy human participants. The nociceptive flexion reflex (NFR) to an electric stimulus was chosen to determine the pain threshold. ⋯ MTZ increases the pain tolerance in healthy participants. The potential benefit of this effect on pain should be investigated more thoroughly in chronic neuropathic pain patients. The NFR might serve as an additional tool for the monitoring of these patients.
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In this review, we explain our current understanding of the molecular basis for pain relief by capsaicin and other transient receptor potential vanilloid subfamily, member 1 (TRPV1) agonists. We summarize disease-related changes in TRPV1 expression and its implications for therapy and potential adverse effects. Last, we provide an overview of the current clinical uses of topical and injectable TRPV1 agonist preparations in both oncologic and nononcologic populations. ⋯ We argue that TRPV1 agonists and antagonists are not mutually exclusive but rather complimentary pharmacologic approaches for pain relief and we predict a "revival" for capsaicin and other TRPV1 agonists in the clinical management of pain associated with inflammation, metabolic imbalances (eg, diabetes), infections (HIV), and cancer, despite the current focus of the pharmaceutical industry on TRPV1 antagonists.
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Although there have been a few case reports in the literature of self-inflicted symptoms presenting as complex regional pain syndrome (CRPS), there has been no systematic study. This report investigates the period prevalence and characteristics of self-induced disorders in patients referred to a comprehensive pain clinic with a diagnosis of CRPS. ⋯ This is the first report of a case series of patients diagnosed as CRPS with self-induced symptoms. We discuss in detail limitations of the study, factors that contribute to the index of suspicion, and the complex nature of the behavior including the overlap between factitious disorder, somatoform disorders, and malingering, whereas we stress the legitimacy of CRPS as a diagnosis.
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Sensory hypersensitivity, central hyperexcitability [lowered nociceptive flexion reflex (NFR) thresholds], and psychologic distress are features of chronic whiplash. However, relationships between these substrates are not clear. This study tested the hypothesis that psychologic distress and catastrophization are correlated with sensory hypersensitivity and NFR responses in chronic whiplash. ⋯ We have demonstrated that psychologic factors have some association with sensory hypersensitivity (cold pain threshold measures) in chronic whiplash but do not seem to influence spinal cord excitability. This suggests that psychologic disorders are important, but not the only, determinants of central hypersensitivity in whiplash patients.