WordNet

a substance that exerts some force or effect
a businessman who buys or sells for another in exchange for a commission (同)factor, broker
any agent or representative of a federal agency or bureau (同)federal agent
a representative who acts on behalf of other persons or organizations
an active and efficient cause; capable of producing a certain effect; "their research uncovered new disease agents"
how long something has existed; "it was replaced because of its age"
a time of life (usually defined in years) at which some particular qualification or power arises; "she was now of school age"; "tall for his eld" (同)eld
begin to seem older; get older; "The death of his wife caused him to age fast"
make older; "The death of his child aged him tremendously"

PrepTutorEJDIC

『代理人』;周旋人 / 働き(作用)を起こすもの;作用物,薬剤 / (政府機関,特にFBI,CIAなどの)部員,機関員
〈U〉(一般に)『年齢』,寿命;〈C〉(個々の)『年齢』,年 / 〈U〉成年(おとなとしての資格・権利を得る年齢;通例18または21歳) / 〈U〉『老齢』;《集合的に》老人たち / 〈U〉(人生の)『一時期』;〈C〉世代(generation) / 〈U〉〈C〉《しばしばA-》(歴史上の)『時代』 / 〈C〉《話》長い間 / 年をとる,ふける;〈物が〉古くなる / 〈年〉'を'とらせる;〈物〉'を'古びさせる

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2015/06/11 00:08:06」(JST)

wiki en

An antiplatelet drug (antiaggregant) is a member of a class of pharmaceuticals that decrease platelet aggregation ^[1] and inhibit thrombus formation. They are effective in the arterial circulation, where anticoagulants have little effect.^{[citation needed]}

They are widely used in primary and secondary prevention of thrombotic cerebrovascular or cardiovascular disease.

Choice of antiplatelet drug

A 2006 review ^[2] states: "...low-dose aspirin increases the risk of major bleeding 2-fold compared with placebo. However, the annual incidence of major bleeding due to low-dose aspirin is modest—only 1.3 patients per thousand higher than what is observed with placebo treatment. Treatment of approximately 800 patients with low-dose aspirin annually for cardiovascular prophylaxis will result in only 1 additional major bleeding episode."

Classification

The class of antiplatelet drugs include:

Irreversible cyclooxygenase inhibitors
- Aspirin
- Triflusal (Disgren)
Adenosine diphosphate (ADP) receptor inhibitors
- Clopidogrel (Plavix)
- Prasugrel (Effient)
- Ticagrelor (Brilinta)
- Ticlopidine (Ticlid)
Phosphodiesterase inhibitors
- Cilostazol (Pletal)
Protease-activated receptor-1 (PAR-1) antagonists
- Vorapaxar (Zontivity)
Glycoprotein IIB/IIIA inhibitors (intravenous use only)
- Abciximab (ReoPro)
- Eptifibatide (Integrilin)
- Tirofiban (Aggrastat)
Adenosine reuptake inhibitors
- Dipyridamole (Persantine)
Thromboxane inhibitors
- Thromboxane synthase inhibitors
- Thromboxane receptor antagonists
  - Terutroban

Usage

Prevention and treatment of arterial thrombosis

Treatment of established arterial thrombosis includes the use of antiplatelet drugs and thrombolytic therapy. Antiplatelet drugs alter the platelet activation at the site of vascular damage crucial to the development of arterial thrombosis.

Aspirin and Triflusal irreversibly inhibits the enzyme COX, resulting in reduced platelet production of TXA₂ (thromboxane - powerful vasoconstrictor that lowers cyclic AMP and initiates the platelet release reaction).
Dipyridamole inhibits platelet phosphodiesterase, causing an increase in cyclic AMP with potentiation of the action of PGI₂ – opposes actions of TXA₂
Clopidogrel affects the ADP-dependent activation of IIb/IIIa complex
Glycoprotein IIb/IIIa receptor antagonists block a receptor on the platelet for fibrinogen and von Willebrand factor. 3 classes:
- Murine-human chimeric antibodies (e.g., abciximab)
- Synthetic peptides (e.g., eptifibatide)
- Synthetic non-peptides (e.g., tirofiban)
Epoprostenol is a prostacyclin that is used to inhibit platelet aggregation during renal dialysis (with or without heparin) and is also used in primary pulmonary hypertension.

Thrombolytic therapy is used in myocardial infarction, cerebral infarction, and, on occasion, in massive pulmonary embolism. The main risk is bleeding. Treatment should not be given to patients having had recent bleeding, uncontrolled hypertension or a hemorrhagic stroke, or surgery or other invasive procedures within the previous 10 days.

Streptokinase forms a complex with plasminogen, resulting in a conformational change that activates other plasminogen molecules to form plasmin.
Plasminogen activators (PA), tissue-type plasminogen activators (alteplase, tenecteplase) are produced by recombinant technology.

Drug toxicity

Drug toxicity may be increased when multiple antiplatelet drugs are used. Gastrointestinal bleeding is a common adverse event seen in many patients.^[3]

References

^ "agents.htm {{{2}}}" at Dorland's Medical Dictionary^{[dead link]}
^ The American Journal of Medicine, Volume 119, Issue 8 , Pages 624-638, August 2006: Systematic Review and Meta-analysis of Adverse Events of Low-dose Aspirin and Clopidogrel in Randomized Controlled Trials Retrieved 2013-02-08
^ Shehab, Nadine; Laurence S. Sperling; Scott R. Kegler; Daniel S. Budnitz (2010-11-22). "National Estimates of Emergency Department Visits for Hemorrhage-Related Adverse Events From Clopidogrel Plus Aspirin and From Warfarin". Arch Intern Med 170 (21): 1926–1933. doi:10.1001/archinternmed.2010.407. PMID 21098354. Retrieved 2010-11-23.

UpToDate Contents

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1. 非ST上昇型急性冠症候群における抗血小板薬 antiplatelet agents in acute non st elevation acute coronary syndromes
2. 脳卒中の二次予防のための抗血小板療法 antiplatelet therapy for secondary prevention of stroke
3. 冠動脈ステント留置術後の抗血小板療法 antiplatelet therapy after coronary artery stenting
4. ST上昇型心筋梗塞における抗血小板剤 antiplatelet agents in acute st elevation myocardial infarction
5. 心血管疾患の二次および一次予防におけるアスピリンの利益とリスク benefits and risks of aspirin in secondary and primary prevention of cardiovascular disease

English Journal

Aspirin and clopidogrel for prevention of ischemic stroke.

Thomson RM, Anderson DC.SourceDepartment of Neurology, University of Minnesota, 420 Delaware St. SE, MMC 295, Minneapolis, MN, 55455, USA, Thom1824@umn.edu.
Current neurology and neuroscience reports.Curr Neurol Neurosci Rep.2013 Feb;13(2):327. doi: 10.1007/s11910-012-0327-y.
This review examines the role of platelets in ischemic stroke, platelet activation mechanisms, aspirin's rise as an antithrombotic agent, clopidogrel's appearance on the stage, a possible role for combination therapy, antiplatelet resistance, practical considerations, and future directions. Reviewed
PMID 23299823

Pharmacokinetics of vicagrel, a promising analog of clopidogrel, in rats and beagle dogs.

Qiu Z, Li N, Wang X, Tian F, Liu Q, Song L, Fan Z, Lu Y, Chen X.SourceCenter of Drug Metabolism and Pharmacokinetics, China Pharmaceutical University, Nanjing, Jiangsu 210009, China.
Journal of pharmaceutical sciences.J Pharm Sci.2013 Feb;102(2):741-9. doi: 10.1002/jps.23394. Epub 2012 Nov 28.
The objective of this investigation was to compare the efficiency of conversion to the active metabolite (AM) from clopidogrel and vicagrel, a novel antiplatelet agent, and support the drug design rationale in the view of the pharmacokinetics. Following intravenous administration to rats, vicagrel w
PMID 23192851

Pharmacological characterization of 1-nitrosocyclohexyl acetate, a long-acting nitroxyl donor that shows vasorelaxant and antiaggregatory effects.

Donzelli S, Fischer G, King BS, Niemann C, Dumond JF, Heeren J, Wieboldt H, Baldus S, Gerloff C, Eschenhagen T, Carrier L, Böger RH, Espey MG.SourceDepartment of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf., Martinistr. 52, D-20246 Hamburg, Germany. s.donzelli@uke.de.
The Journal of pharmacology and experimental therapeutics.J Pharmacol Exp Ther.2013 Feb;344(2):339-47. doi: 10.1124/jpet.112.199836. Epub 2012 Dec 4.
Nitroxyl (HNO) donors have potential benefit in the treatment of heart failure and other cardiovascular diseases. 1-Nitrosocyclohexyl acetate (NCA), a new HNO donor, in contrast to the classic HNO donors Angeli's salt and isopropylamine NONOate, predominantly releases HNO and has a longer half-life.
PMID 23211362

Japanese Journal

Thrombolytic and Antiplatelet Effects of a Novel Plasminogen Activator from the Venom of Gloydius Brevicaudus Viper

Zhang Zhiqiang,Lin Lili,Zhang Jinhua,Zhang Qiong,Zhao Ningning,Wu Linqun,Chen Jianji,Wu Zhiqiang,Wu Guotu,Lin Jianzhong,Chen Yu,Xu Yunlu
Journal of Atherosclerosis and Thrombosis advpub(0), 2015
… Aim: To investigate the thrombolytic and antiplatelet effects of a novel plasminogen activator from the venom of the Gloydius brevicaudus viper (GBV-PA) in vitro and in vivo.Methods: Thrombolytic experiments were performed in rabbit models of ear vein thrombosis and carotid artery thrombosis and in dog model of acute cerebral infarction. …
NAID 130005071055

Analysis of the Interaction between Clopidogrel, Aspirin, and Proton Pump Inhibitors Using the FDA Adverse Event Reporting System Database

Suzuki Yukiya,Suzuki Honami,Umetsu Ryogo [他],Uranishi Hiroaki,Abe Junko,Nishibata Yuri,Sekiya Yasuaki,Miyamura Nobuteru,Hara Hideaki,Tsuchiya Teruo,Kinosada Yasutomi,Nakamura Mitsuhiro
Biological and Pharmaceutical Bulletin 38(5), 680-686, 2015
… Clopidogrel is an antiplatelet agent widely used in combination with aspirin to limit the occurrence of cardiovascular (embolic/thrombotic) events. … Consensus guidelines recommend proton pump inhibitors (PPIs) as a gastrointestinal (GI) prophylactic measure for all patients receiving dual antiplatelet therapy with clopidogrel and aspirin. …
NAID 130005068091

次世代型口腔内崩壊錠に求められる臨床的機能性とは？

並木徳之
薬学雑誌. 乙号 135(2), 237-243, 2015
… In this symposium, we will discuss a next-generation OD formulation known as PLETAAL OD, a high-dose antiplatelet agent, and will present the results of validation tests performed in our laboratory pertaining to high tablet strength, superior disintegration property, high wicking capacity, and storage stability with high moisture resistance. …
NAID 130004756477

★リンクテーブル★

リンク元	「抗血小板薬」「血小板凝集阻害薬」「platelet aggregation inhibitor」「platelet inhibitor」
関連記事	「agent」「age」