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rio24

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[交流] 10个金币求助--阿司匹林引起胃肠道出血的原因

一道考题,分值比较大
长期服用阿司匹林有时会引起胃肠道出血,为什么?


希望有大侠能详细解答,谢谢
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anyetang

木虫 (正式写手)

★ ★ ★ ★ ★ ★
karl2100(金币+1,VIP+0):多谢提供!
rio24(金币+5,VIP+0):谢谢解答~!
阿司匹林是一个解热镇痛抗炎药,其作用机制是抑制体内前列腺素(PG)合成,PG是体内生物活性很强、很广的物质。其中PGE2具有致热、致炎、致痛、保护胃黏膜等作用。PGE2能防止有害因子损伤胃粘膜,能预防化学刺激引起的胃粘膜出血、糜烂与坏死,发挥细胞或粘膜保护作用。长期使用阿司匹林,由于抑制了前列腺素合成酶(COX—1),干扰PGS(主要为PGE2)合成,使PGE2生成减少,胃黏膜的屏障作用减弱,刺激胃粘膜,引起上腹部不适,胃灼痛,甚至诱发或加重溃疡和出血。
2楼2007-12-22 02:17:47
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自由鱼187

木虫 (初入文坛)

学习了。。谢谢
3楼2007-12-22 08:50:24
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Acode

木虫 (小有名气)


karl2100(金币+1,VIP+0):谢谢!
个人认为还有一个原因,就是阿司匹林抑制凝血恶烷(TXA2)的形成,从而抗凝。
因为TXA2同PGE为同类物质,也受到环加氧酶调节。
4楼2007-12-22 17:35:25
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耗子怕猫

金虫 (小有名气)

阿司匹林会影响凝血功能
5楼2007-12-22 19:04:12
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sai00fuji

金虫 (正式写手)


karl2100(金币+1,VIP+0):谢谢发言!
阿司匹林与其他解热抗炎药不同,它不可逆的抑制cox,使内源性PG(外源性的是至炎物质,内源性的可以保护胃粘膜)减少。
6楼2008-01-01 13:54:18
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liurong1116

铜虫 (初入文坛)

主要原因有这样几点:第一、非选择性的抑制了环氧化酶的两种同工酶,COX—1抑制降低了对胃粘膜的保护;还有一个原因,阿司匹林自身对胃粘膜细胞存在损伤,阿司匹林是弱酸性的药物,在胃内的酸性环境中药物是非解离状态,这时容易透过胃粘膜细胞膜进入细胞内,而细胞内是弱碱性的环境,那么弱酸性的药物分解成为解离状态,这样就不容易在此透过胞膜出细胞,因此会在细胞内大量堆积,对胃粘膜造成损伤。
7楼2008-01-22 23:19:41
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fxzxp

铁杆木虫 (小有名气)


karl2100(金币+1,VIP+0):多谢提供!
建议看看下面这本书吧。
Aspirin_and_Related_Drugs

Contents
2 THE INDUSTRIAL HISTORY OF ANALGESICS: THE EVOLUTION OF
ANALGESICS AND ANTIPYRETICS
J.R. McTavish
Recognition of Pain
Therapeutic Nihilism and Fevers
The Organic Chemical Industry
The Salicylates
The Value of a Good Name
Conclusion
References
4 PHARMACOKINETICS AND METABOLISM OF THE SALICYLATES
G.G. Graham, M.S. Roberts, R.O. Day and K.D. Rainsford
Introduction
Absorption of Aspirin and Salicylate
Distribution of Aspirin and Salicylate
Elimination of Aspirin
Elimination of Salicylate
Metabolic Pathways of Salicylate
Factors Controlling the Elimination of Aspirin and Salicylate
Kinetics of Elimination of Salicylate
Pro-Drugs
Analytical Methods for the Salicylates
Salicylate Derivatives
Diflunisal
Salicylamide
References
5 METABOLISM AND PHARMACOKINETICS OF IBUPROFEN
G.G. Graham and K.M. Williams
Introduction
Absorption
Distribution
Elimination
Half-life and Clearance
Factors Affecting the Elimination of Ibuprofen
Pharmacokinetics, Plasma Concentrations and Clinical Response
Analytical Methods
References
6 PHARMACOKINETICS AND METABOLISM OF PARACETAMOL
(ACETAMINOPHEN)
G.G. Graham and M. Hicks
Introduction
Absorption
Distribution
© 2004 K.D. Rainsford
Elimination
Half-life and Clearance
Factors Affecting the Elimination of Paracetamol
Metabolism of Pro-drugs
Analytical Methods
References
7 PHARMACOLOGY AND BIOCHEMISTRY OF SALICYLATES AND
RELATED DRUGS
K.D. Rainsford
Introduction
Anti-inflammatory Effects
Biochemical Effects of Salicylates in Relation to their Anti-inflammatory Actions
Analgesic Activity
Antipyresis
References
Appendix to Chapter 7
8 SIDE EFFECTS AND TOXICOLOGY OF THE SALICYLATES
K.D. Rainsford
Introduction
Occurrence of Adverse Events from NSAIDs, including Aspirin
Gastrointestinal Side Effects
Hepatotoxicity
Nephropathy
Hypersensitivity Reactions and Asthma
Teratogenesis and Pregnancy
Miscellaneous Side Effects
Acute Salicylate Poisoning
Conclusions
References
9 REYE’S SYNDROME AND ASPIRIN
J.F.T. Glasgow and S.M. Hall
Introduction
Background
Definition
Clinical Features
Investigations
© 2004 K.D. Rainsford
Differential Diagnosis
Aetiology and Pathogenesis
Management Principles
The Future
Conclusion
Acknowledgements
References
10 SALICYLATES IN THE TREATMENT OF ACUTE PAIN
K.D. Rainsford
Introduction
Concepts of the Mode of Action in Acute Pain
Early Observations in Various Pain States
Efficacy in Various Pain Conditions
Comparative Effects in Acute Pain States
References
11 ACETYLSALICYLIC ACID FOR THE PREVENTION AND TREATMENT
OF THROMBOEMBOLIC DISEASES
K.E. Webert and J.G. Kelton
The Role of Platelets in Haemostasis and Thrombosis
The Role of Platelets in Acute and Chronic Vascular Injury
Effects of Acetylsalicylic Acid on Platelet Function
Pharmacokinetics of ASA
Dose–Effect Relationships of ASA
The Effects of ASA on Coagulation Factors, other than Platelets
ASA for the Prevention of Vascular Thromboembolic Disease: Epidemiological Studies
ASA for the Treatment of Acute Vascular Thromboembolic Events
Novel Analogues of Salicylates and Further Developments
References
12 USE OF SALICYLATES IN RHEUMATIC AND RELATED CONDITIONS
W.W. Buchanan, W.F. Kean and K.D. Rainsford
Introduction
History
Rheumatoid Arthritis
Osteoarthritis
Miscellaneous musculoskeletal disorders
Drug Kinetics and Monitoring
© 2004 K.D. Rainsford
Adverse Events in Rheumatic Patients
Factors Affecting Side Effects and Therapeutic Effects
Toxicity
Conclusions
References .
13 ASPIRIN AND NSAIDs IN THE PREVENTION OF CANCER, ALZHEIMER’S
DISEASE AND OTHER NOVEL THERAPEUTIC ACTIONS
K.D. Rainsford
Introduction
Prevention of Colorectal and Other Cancers
Alzheimer’s Disease and Related Dementias
Copper Salicylates in the Treatment of Inflammatory Diseases and Cancer
Therapeutic Uses of Aspirin in Pregnancy
Kawasaki Disease
Perturbed Metabolic States
Immunological Effects
Other Possible Uses
Miscellaneous
References

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[ Last edited by fxzxp on 2008-1-23 at 10:08 ]
8楼2008-01-23 10:02:16
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乙酰水杨酸

木虫 (正式写手)

KOP

阿司匹林


karl2100(金币+1,VIP+0):多谢提供!
阿司匹林本身为水杨酸酯结构,虽然酯化了酚羟基,但仍然带1个游离的羧基,对胃肠道具有刺激作用,此外阿司匹林作为1种解热镇痛药其机理为抑制环氧合酶减少前列腺素PG的产生,而PG主要有保护胃黏膜的作用因此阿司匹林容易引起胃肠道出血
浮世绘卷拓不懂濯清涟不妖
9楼2008-02-17 10:44:39
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