英和和英

出典:『Wikipedia』 (2011/01/30 19:44 UTC 版)

英語による解説

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Dipipanone is an extremely strong opioid used for very severe pain in cases where morphine is indicated but cannot be used due to the patient being allergic to morphine . The main preparation of the drug commercially available is mixed with cyclizine (Diconal, Wellconal) which has the advantage of reducing nausea, vomiting and histamine release associated with strong opioid therapy. It is now unavailable in most countries of the world either by laws prohibiting its medicinal use as in the United States or by falling out of production as more modern analgesics took its market share. The UK, Ireland and South Africa are known to continue to use the substance but it is infrequently prescribed.( Diconal is no longer available in Republic of Ireland and has not been for at least 5-10 years but should still be available in Northern Ireland as it is part of the UK ) Chemically, dipipanone belongs to the class of opioids called the 4,4-diphenylheptane-3-ones. It closely resembles methadone, the only structural difference being the N,N-dimethyl moiety of methadone being replaced with a piperidine ring. Its use is discouraged because of the abuse risk- the BNF marks the substance as "less suitable for prescribing" along with other older compounds such as pethidine and pentazocine with unusual abuse patterns. The combination with cyclizine leads to a very strong rush if the drug is injected, however the tablets contain insoluble binders which led to many limb amputations and some fatalities. During the late 1970s to early 1980s in the UK, many deaths were blamed on misuse of this preparation. As supplies became unavailable, opiate users would mix crushed methadone tablets or Physeptone ampoules with crushed Valoid (a cyclizine containing antihistamine) tablets in an attempt to replicate the effect of Diconal. The general procedure for synthesis is illustrated by nucleophilic attack of diphenylacetonitrile on 2-chloro-1-dimethylamino-ethane. The resulting aminonitrile is then converted to the ethyl ketone with ethyl magnesium bromide by way of the ketimine which is hydrolyzed by cold aqueous acid.