The Clinical journal of pain
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Opioid-induced hyperalgesia (OIH) is most broadly defined as a state of nociceptive sensitization caused by exposure to opioids. The state is characterized by a paradoxical response whereby a patient receiving opioids for the treatment of pain may actually become more sensitive to certain painful stimuli. The type of pain experienced may or may not be different from the original underlying painful condition. ⋯ OIH seems to be a distinct, definable, and characteristic phenomenon that may explain loss of opioid efficacy in some cases. Clinicians should suspect expression of OIH when opioid treatment 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 pain as previously observed. This review highlights the important mechanistic underpinnings and clinical ramifications of OIH and discusses future research directions and the latest clinical evidence for modulation of this potentially troublesome clinical phenomenon.
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This paper describes characteristics of opioid use episodes for noncancer pain and defines thresholds for de facto long-term opioid therapy. ⋯ Long-term opioid therapy was characterized by the diversity in medications prescribed, dosage levels, and frequency of use. The proposed threshold for long-term opioid therapy provides a checkpoint for physicians to review whether an explicit decision to sustain opioid therapy has been reached, and to ensure that a documented treatment plan and provisions for monitoring medication use and patient outcomes are in place.
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Prescription opioid misuse is a growing problem in the United States. There are limited data to illuminate the nature of this issue. The Internet seems to be a novel approach in surveying populations of opioid users. An Internet-based survey of nonmedical opioid users visiting informational drug websites was used to measure rates of nonmedical use and characterize users. ⋯ This project demonstrates the feasibility of conducting product-specific, online surveys with rapid recruitment of participants from websites. This approach differentiates rates of nonmedical use of specific prescription opioids and provides other insights into individuals who nonmedically use opioids.
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Randomized Controlled Trial
Effect of chronic oral gabapentin on capsaicin-induced pain and hyperalgesia: a double-blind, placebo-controlled, crossover study.
There is an abundance of literature on the efficacy of gabapentin for the treatment of neuropathic pain. Two studies have demonstrated an effect of a single dose of gabapentin on experimental cutaneous hyperalgesia. This study evaluated the effect of chronic delivery of oral gabapentin on experimentally induced cutaneous hyperalgesia. ⋯ This study demonstrated a lack of effect of the chronic delivery of oral gabapentin on experimentally induced cutaneous hyperalgesia. The discrepancy of this finding with other studies using single oral doses may be the result of differences in the models used and differences in drug kinetics and plasma levels. The results of this study do not correlate with the clinical studies on gabapentin, which demonstrate efficacy at 1800 mg/d.
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Review
Predicting opioid misuse by chronic pain patients: a systematic review and literature synthesis.
Opioids can provide relief for people with chronic pain. However, a minority may develop aberrant drug behaviors. A critical issue is identifying "at-risk" patients. ⋯ Review of the published studies reveals that no one procedure or set of predictor variables is sufficient to identify CPP at-risk for opioid misuse or abuse. There is a scarcity of evidence regarding characteristics that predict aberrant behavior before beginning long-term opioids. Several predictors have been identified. Strong predictors include a personal history of illicit drug and alcohol abuse. Demographic factors have also been reported, but the results are not consistent. Prospective studies, especially ones with CPP who have not already been started on chronic opioid therapy, are needed.