Cancer
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Clinical Trial Controlled Clinical Trial
Evaluation of a cancer pain model for the testing of long-acting analgesics. The effect of MS Contin in a double-blind, randomized crossover design.
A double-blind, double-dummy, crossover study compared oral controlled-release morphine sulfate (MS Contin tablets [MSC], Purdue Frederick, Norwalk, CT) every 12 hours, and immediate-release morphine sulfate (IRMS) tablets, every 4 hours, in 14 evaluable patients with chronic cancer pain. The test model described showed assay sensitivity for steady-state analgesia, requiring relatively few subjects to yield statistical significance in pharmacologic potency estimates. Initial doses were the calculated equivalents of about one third the previous opioid requirements or at least 30 mg MSC every 12 hours or 15 mg IRMS every 4 hours. ⋯ MS Contin exhibits a 12-hour duration of action as previously shown in other well-controlled trials. A problem of pain exacerbation at the start of each study phase was found to be associated with the design of this study. It may be resolved with a higher initial study dose and/or use of a patient-controlled analgesia device for parenteral rescue doses.
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Cancer pain can be divided into three classes: somatic, visceral, and deafferentation. Somatic and visceral pain result from activation of nociceptors by tumor infiltration of tissues and from secondary inflammatory changes with release of algesic chemicals that act to sensitize nociceptors. Pain may be experienced locally (somatic and visceral) or referred to remote cutaneous sites (visceral). ⋯ Somatic, visceral, and deafferentation pain may be complicated by sympathetically maintained pain, in which efferent sympathetic activity promotes persistent pain, hyperpathia, and vasomotor and sudomotor changes after tissue injury from cancer or its therapy. The neurobiology of cancer pain is complex and incompletely understood. This article summarizes current knowledge in this area and briefly discusses approaches to cancer pain management that are based on this knowledge.
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Randomized Controlled Trial Clinical Trial
Oral controlled-release morphine sulfate. Analgesic efficacy and side effects of a 100-mg tablet in cancer pain patients.
Fifty-one cancer pain patients with limited opioid exposure participated in a randomized, double-blind, repeated-dose, parallel-group comparison of two dosage strengths of the controlled-release morphine preparation, MS Contin tablets (The Purdue Frederick Company, Norwalk, CT). The patients were first stabilized on immediate-release oral morphine 30 mg every 4 hours, with 15 mg available every 2 hours as needed for breakthrough pain ("rescue" dose). Each patient then received either one 100 mg MS Contin tablet or three 30-mg MS Contin tablets every 12 hours, with rescue medication as needed, for 3 days. ⋯ In the study population as a whole, pain intensity was lower and total morphine intake higher during the period on controlled-release morphine. These data establish comparable analgesic efficacy and side effect potential of these two dosage strengths and confirm a 12-hour duration of effect for both. The improved analgesia on the controlled-release morphine may be attributable to increased consumption of drug resulting from improved compliance.