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Nalbuphine is a semi-synthetic opioid used commercially as an analgesic under a variety of trade names, including Nubain and Manfine. ==Medical uses== Nalbuphine is indicated for the relief of moderate to severe pain. It can also be used as a supplement to balanced anesthesia, for preoperative and postoperative analgesia, and for obstetrical analgesia during labor and delivery. Although nalbuphine possesses opioid antagonist activity, there is evidence that in nondependent patients it will not antagonize an opioid analgesic administered just before, concurrently, or just after an injection. Therefore, patients receiving an opioid analgesic, general anesthetics, phenothiazines, or other tranquilizers, sedatives, hypnotics, or other CNS depressants (including alcohol) concomitantly with Nalbuphine may exhibit an additive effect. When such combined therapy is contemplated, the dose of one or both agents should be reduced. In addition to the relief of pain, the drug has been studied as a treatment for morphine induced pruritus (itching). Pruritus is a common side effect of morphine or other pure mu agonist opioid administration. Kjellberg et al. (2001) published a review of clinical trials relating to the prevalence of morphine induced pruritus and its pharmacologic control. The authors state that nalbuphine is an effective anti-pruritic agent against morphine induced pruritus. The effect may be mediated via central nervous system mechanisms. Pan (1998) summarizes the evidence that activation at the pharmacological level of the opioid κ-receptor antagonizes various opioid μ-receptor mediated actions in the brain. The authors states that the neural mechanism for this potentially very general opioid μ-receptor antagonizing function by the opioid κ-receptor may have broad applications in the treatment of central nervous system mediated diseases. He does not state, however, that nalbuphine's pharmacological mechanism of action for pruritus is the result of this interaction between the two opioid receptors. Morphine induced pruritus syndrome may also be caused by release of histamine from mast cells in the skin (Gunion et al. (2004). Paus et al. (2006) report that opioid μ-receptors and opioid κ-receptors are located in skin nerves and keratinocytes. Levy et al. (1989) reviewed the literature on the relationship of opioid mediated histamine release from cutaneous mast cells to the etiology of hypotension, flushing and pruritus. The authors investigated the relative abilities of various opioids to induce histamine release mediated increased capillary permeability and tissue edema (“wheal response” ) and cutaneous vasodilatation and local redness (“flare response”) when subjects were intradermally injected with 0.02 ml equimolar concentrations of 5 x 10-4 M. Nalbuphine did not produce either a wheal or flare response. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Nalbuphine」の詳細全文を読む スポンサード リンク
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