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Cinnarizine is a medication derivative of piperazine, and characterized as an antihistamine and a calcium channel blocker, it is also known to promote cerebral blood flow, and so is used to treat cerebral apoplexy, post-trauma cerebral symptoms, and cerebral arteriosclerosis. However, it is more commonly prescribed for nausea and vomiting due to motion sickness or other sources such as chemotherapy, vertigo, or Ménière's disease. Cinnarizine was first synthesized by Janssen Pharmaceutica in 1955. The nonproprietary name is derived from the cinnamyl substituent on one of the nitrogen atoms, combined with the generic ending "-rizine" for "antihistaminics/cerebral (or peripheral) vasodilators".〔(【引用サイトリンク】title=The use of stems in the selection of International Nonproprietary Names (INN) for pharmaceutical substances 2011 )〕 It is not available in the United States or Canada. It is manufactured and marketed in Bangladesh under the trade name Suzaraon by Rephco Pharmaceuticals Limited. It has also been cited as one of the most used drugs for seasickness within the British Royal Navy. ==Medical uses== Cinnarizine is predominantly used to treat nausea and vomiting associated with motion sickness,〔 vertigo,〔 Ménière's disease,〔 or Cogan's syndrome.〔 In fact, it is one of only a select few drugs that has shown a beneficial effect in the chronic treatment of the vertigo and tinnitus, associated with Meniere's disease. However, due to increased levels of drowsiness caused by the medication, it is generally of limited use in pilots and aircrew who must be dependably alert.〔 In a clinical study (n=181), treatment with cinnarizine reduced the occurrence of moderate vertigo experience by 65.8% and extreme vertigo by 89.8%.〔 It acts by interfering with the signal transmission between vestibular apparatus of the inner ear and the vomiting centre of the hypothalamus by limiting the activity of the vestibular hair cells which send signals about movement.〔 The disparity of signal processing between inner ear motion receptors and the visual senses is abolished, so that the confusion of brain whether the individual is moving or standing is reduced. Vomiting in motion sickness could be a physiological compensatory mechanism of the brain to keep the individual from moving so that it can adjust to the signal perception, but the true evolutionary reason for this malady is currently unknown. When prescribed for balance problems and vertigo, cinnarizine is typically taken two or three times daily depending on the amount of each dose and when used to treat motion sickness, the pill is taken at least two hours before travelling and then again every four hours during travel.〔(【引用サイトリンク】title=Stugeron 15 )〕 However, a recent 2012 study comparing the effects of cinnarizine to transdermal scopolamine for the treatment of seasickness, concluded that scopolamine was reported as significantly more effective and as having fewer adverse side effects than cinnarizine. This led to the conclusion that transdermal scopolamine is likely a better option for the treatment of motion sickness in naval crew and other sea travelers. Beyond an anti-vertigo treatment, cinnarizine could be also viewed as a nootropic drug because of its vasorelaxating abilities (due to calcium channel blockage), which happen mostly in brain and the fact that it is also used as a labyrinthine sedative. Cinnarizine inhibits the flow of calcium into red blood cells, which increases the elasticity of the cell wall, thereby increasing their flexibility and making the blood less viscous.〔 This allows the blood to travel more efficiently and effectively through narrowed vessels in order to bring oxygen to damaged tissue.〔 It is also effectively combined with other nootropics, primarily piracetam; in such combination each drug potentiates the other in boosting brain oxygen supply.〔RomPharm. Pyracin (piractam 400 mg and cinnarizine 25 mg). 2008 (2012 10/20 ).〕 An animal study comparing the effectiveness of cinnarizine and flunarizine (a derivative of cinnarizine that is 2.5-15 times stronger for treatment of transient global cerebral ischemia, it was found that cinnarizine helped to improve the functional abnormalities of ischemia, but did not help with damage to the neurons. Flunarizine, on the other hand, offered more neuronal protection, but was less effective in treating subsequent behavioral changes.〔 Additionally, cinnarizine can be used in scuba divers without an increased risk of central nervous system oxygen toxicity which can result in seizures, and is a high risk in closed-circuit oxygen diving. This is also relevant to divers who could potentially have to undergo hypobaric decompression therapy, which uses high oxygen pressure and could also be affected by any cinnarizine-induced CNS oxygen toxicity risk. However, cinnarizine does not heighten toxicity risk, and in fact, evidence even seems to suggest that cinnarizine may be beneficial in helping delay O2 toxicity in the central nervous system.〔 There is also evidence that cinnarizine may be used as an effective anti-asthma medication when taken regularly. Cinnarizine has also been found to be a valuable second-line treatment for idiopathic urticarial vasculitis. 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「cinnarizine」の詳細全文を読む スポンサード リンク
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