Journal of pain and symptom management
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The metabolism of opioids closely relates to their chemical structure. Opioids are subject to O-dealkylation, N-dealkylation, ketoreduction, or deacetylation leading to phase-I metabolites. By glucuronidation or sulfatation, phase-II metabolites are formed. ⋯ By this, it may play an important role in the clinical effects of morphine. Several other opioids, such as meperidine and perhaps also morphine and hydromorphone, produce metabolites with neuroexcitatory effects. In sum, the evidence suggests that the metabolites of several opioids account for an important part of the clinical effects that must be considered in clinical practice.
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Hydromorphone is a semi-synthetic opioid that has been used widely for acute pain, chronic cancer pain and to a lesser extent, in chronic nonmalignant pain. Its pharmacokinetics and pharmacodynamics have been well studied, including immediate release oral preparations, a variety of slow release oral preparations, as well as administration through intravenous, subcutaneous, epidural, intrathecal and other routes. ⋯ There is no evidence that hydromorphone has any greater abuse liability than other opioids. Further research is needed to address remaining areas of uncertainty: equianalgesic ratios; relative risk of toxicity compared with other opioids, its use in nonmalignant pain, and the role of specific hydromorophone metabolites in the development of toxicity, particularly in association with organ failure.
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Pain is the cancer-related event that is most disruptive to the cancer patient's quality of life. Although bone cancer pain is one of the most severe and common of the chronic pains that accompany breast, prostate, and lung cancers, relatively little is known about the mechanisms that generate and maintain this pain. Recently, we developed a mouse model of bone cancer pain. ⋯ Humans suffering from bone cancer pain generally require significantly higher doses of morphine as compared to individuals with inflammatory pain and in the mouse model the doses of morphine required to block bone cancer pain-related behaviors were 10 times that required to block peak inflammatory pain behaviors of comparable magnitude induced by hindpaw injection of complete Freund's adjuvant (CFA; 1-3 mg/kg). As these animals were treated acutely, there was not time for morphine tolerance to develop and the rightward shift in analgesic efficacy observed in bone cancer pain versus inflammatory pain suggests a fundamental difference in the underlying mechanisms that generate bone cancer versus inflammatory pain. These results indicate that this model will be useful in defining drug therapies that are targeted for complex bone cancer pain syndromes.
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In Japan, palliative care team (PCT) services have been covered by National Health Insurance since 2002. The primary aims of this study were to compare the characteristics of patients who received PCT services with those admitted to palliative care units (PCU), and to clarify the medical treatments and symptom improvement during the first week after consultation with the PCT. This was a prospective audit study of 111 consecutive cancer patients referred to the PCT in Seirei Mikatabara Hospital and a comparison group of 100 consecutive patients admitted to PCU. ⋯ However, no significant improvements were observed in symptom scores of fatigue, dry mouth, somnolence, and delirium. A median of 3 interventions was performed for each patient, and the most common interventions were administration of NSAIDs, opioids, centrally-acting antiemetics, and steroids. These data indicate that a PCT was successfully implemented in Seirei Mikatabara Hospital, and may contribute to symptom improvement in cancer patients.