Pain physician
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Opioid-induced hyperalgesia (OIH) is defined as a state of nociceptive sensitization caused by exposure to opioids. The condition is characterized by a paradoxical response whereby a patient receiving opioids for the treatment of pain could actually become more sensitive to certain painful stimuli. The type of pain experienced might be the same as the underlying pain or might be different from the original underlying pain. ⋯ Clinicians should suspect OIH when opioid treatment's effect seems to wane in the absence of disease progression, particularly if found in the context of unexplained pain reports or diffuse allodynia unassociated with the original pain, and increased levels of pain with increasing dosages. The treatment involves reducing the opioid dosage, tapering them off, or supplementation with NMDA receptor modulators. This comprehensive review addresses terminology and definition, prevalence, the evidence for mechanism and physiology with analysis of various factors leading to OIH, and effective strategies for preventing, reversing, or managing OIH.
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Review
A systematic review of observational studies on the effectiveness of opioid therapy for cancer pain.
The prevalence of cancer-related pain and residual pain in cancer survivors is high. Opioids serve as the gold standard for treating moderate to severe cancer pain. The evaluation of the effectiveness of opioids in chronic non-cancer pain has shown a lack of effectiveness, or rather weak evidence for some of the drugs. In contrast, in cancer pain, opioids are expected to be very effective. Due to the nature of the disease, there is evidence of a paucity of randomized trials investigating opioid effectiveness in cancer pain on a long-term basis. Consequently, the effectiveness of opioids in managing cancer-related pain warrants further evidence-based review beyond randomized trials, including observational studies and case reports. ⋯ This systematic review of observational studies indicates Level II-3 evidence for effectiveness of opioids in cancer pain therapy, with 1C/strong recommendation based on observational studies, which could change based on future evidence.
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Neuromodulation with spinal cord stimulation is a proven cost effective treatment for the management of common conditions such as chronic radicular leg pain from failed back surgery syndrome, complex regional pain syndrome, and other painful neuropathic pain syndromes. The traditionally instructed method for percutaneous spinal cord stimulator (SCS) lead placement promotes the use of a "loss of resistance" (LOR) technique under anteroposterior (AP) fluoroscopic guidance to assure midline lead placement and proper entry into the epidural space. ⋯ This fluoroscopic technique provides an alternative means for placing percutaneous cervical SCS leads without the use of the traditional loss of resistance technique.
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Opioids have been utilized for thousands of years to treat pain and their use continues to escalate. It is estimated that 90% of the patients who present to pain centers and receive treatment in such facilities are on opioids. However, in contrast to increasing opioid use and the lack of evidence supporting long-term effectiveness in chronic non-cancer pain, is the escalating misuse of prescription opioids, including abuse and diversion. There is also uncertainty about the incidence and clinical salience of multiple, poorly characterized adverse drug events, including endocrine dysfunction, immunosuppression, infectious disease, opioid-induced hyperalgesia, overdoses, deaths, and psychosocial and economic implications. ⋯ This comprehensive review illustrates the lack of literature on long-term opioid therapy; thus, opioid therapy should be provided with great restraint and caution, based on the weak evidence available.
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The present evidence illustrates that the placebo effect depends on a variety of neurochemical and neurophysiological mechanisms, which are measurable and modifiable. However, the placebo response is inexorably tied to the treatment context. All medical treatments take place in a particular context; this context includes the therapist's attitudes, psychosocial factors affecting the therapeutic relationship, and the patient's mindset. ⋯ On the contrary, they should try to potentiate it, since this is a very important clinical implication. From the research perspective, the emerging knowledge of placebo continues to cast doubts on the appropriateness of the double-blind placebo-control design in assessing efficacy of treatment--specifically involving interventional techniques or surgery. The research setting itself may introduce nocebo hyperalgesia.