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Morphine, sold under many trade names,〔 is a pain medication of the opiate type. It acts directly on the central nervous system (CNS) to decrease the feeling of pain. It can be used for both acute pain and chronic pain. Morphine is also frequently used for pain from myocardial infarction and during labour. It can be administered orally, intramuscularly, subcutaneously, intravenously, into the space around the spinal cord, or rectally.〔 Maximum effect is around 20 min when given intravenously and 60 min when given by mouth while duration of effect is between three and seven hours.〔 Long acting formulations also exist.〔(【引用サイトリンク】url=http://www.drugs.com/monograph/morphine-sulfate.html )〕 Potentially serious side effects include a decreased respiratory effort and low blood pressure. Morphine has a high potential for addiction and abuse. If the dose is reduced after long term use withdrawal may occur. Common side effects include drowsiness, vomiting, and constipation. Caution is advised when used during pregnancy or breast feeding as morphine will affect the infant.〔 Morphine was first isolated between 1803 and 1805 by Friedrich Sertürner. This is generally believed to be the first isolation of an active ingredient from a plant. Merck began marketing it commercially in 1827.〔 Morphine was more widely used after the invention of the hypodermic syringe in 1853–1855.〔〔 Sertürner originally named the substance ''morphium'' after the Greek god of dreams, Morpheus, for its tendency to cause sleep. The primary source of morphine is isolation from poppy straw of the opium poppy. In 2013 an estimated 523,000 kilograms of morphine were produced.〔 About 45,000 kilograms were used directly for pain, an increase over the last twenty years of four times.〔 Most use for this purpose was in the developed world. About 70% of morphine is used to make other opioids such as hydromorphone, oxycodone, heroin, and methadone.〔 It is a Schedule II drug in the United States,〔 Class A in the United Kingdom, and Schedule I in Canada. It is on the WHO Model List of Essential Medicines, a list of the most important medications needed in a basic health system. ==Medical uses== Morphine is primarily used to treat both acute and chronic severe pain. It is also used for pain due to myocardial infarction and for labor pains.〔(【引用サイトリンク】 url = http://www.drugs.com/monograph/morphine-sulfate.html )〕 However, concerns exist that morphine may increase mortality in the setting of non ST elevation myocardial infarction. Morphine has also traditionally been used in the treatment of acute pulmonary edema.〔 A 2006 review, though, found little evidence to support this practice. Immediate-release morphine is beneficial in reducing the symptom of acute shortness of breath due to both cancer and noncancer causes. In the setting of breathlessness at rest or on minimal exertion from conditions such as advanced cancer or end-stage cardiorespiratory diseases, regular, low-dose sustained-release morphine significantly reduces breathlessness safely, with its benefits maintained over time. Its duration of analgesia is about three to seven hours.〔〔 Morphine is also available as a slow-release formulations for opiate substitution therapy (OST) in Austria, Bulgaria, and Slovenia, for addicts who cannot tolerate either methadone or buprenorphine. 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「morphine」の詳細全文を読む スポンサード リンク
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