Platelets inhibitor

Platelet-activating Factor Platelet Aggregation Inhibitors Platelet-derived Growth Factor Receptor Platelet Inhibitors Platelets... 

The widely used platelet inhibitor aspirin or acetylsalicylic acid, by acetylating the enzyme cyclooxygenase, inhibits platelet function by preventing the formation of thromboxane A2 and the synthesis of prostaglandin I2 (PGI2) (68). Aspirin has been used in combination with other antiplatelet agents such as ticlopidine, which inhibits ADP-induced platelet aggregation (69). 

A short-acting platelet inhibitor called dipyridamole functions by maintaining a high level of cAMP within the platelets by inhibiting the enzyme phosphodiesterase, which would otherwise degrade cAMP. It also raises the adenosine concentration in plasma by decreasing its cellular uptake and degradation (70). 

Zell M., Husser C., and Hopfgartner G., 1997b. Column-switching high-performance liquid chromatography combined with ionspray tandem mass spectrometry for the simultaneous determination of the platelet inhibitor Ro 44-3888 and its pro-drug and precursor metabolite in plasma. J Mass Spectrom 32 23. 

The risk of these events is increased by the use of indwelling epidural catheters for administration of analgesia or by the concomitant use of drugs affecting hemostasis, such as nonsteroidal anti-inflammatory drugs (NSAIDs), platelet inhibitors, or other anticoagulants. The risk also appears to be increased by traumatic or repeated epidural or spinal puncture. 

Safety and efficacy with platelet inhibitors other than aspirin (e.g, glycoprotein Ilb/IIIa inhibitors) not established... 

Increased risk of spinal/epidural hematomas with neuraxial anesthesia or spinal puncture. Risk is further increased by use of indwelling spinal catheters, repeated/ traumatic epidural/spinal puncture, or use of drugs affecting hemostasis (NSAIDs, anticoagulants, platelet inhibitors). 

Drug interactions The safety and effectiveness of Angiomax have not been established when used in conjunction with platelet inhibitors other than aspirin. 

Nitric oxide (NO) N=0 Vasodilator, platelet inhibitor, immune regulator, neurotransmitter... 

Chadderdon, R.C. and Cappello, M. (1999) The hookworm platelet inhibitor functional blockade of integrins GPIIb/llla (alphallbbeta3) and GPIa/lla (alpha2beta1) inhibits platelet aggregation and adhesion in vitro. Journal of Infectious Diseases 179, 1235-1241. 

Del Valle, A., Jones, B.F., Harrison, L.M., Chadderdon, R.C. and Cappello, M. (2003) Isolation and molecular cloning of a secreted hookworm platelet inhibitor from adult Ancylostoma caninum. Molecular and Biochemical Parasitology 129, 157-1 77. 

Normal hemostasis is a balance between excessive and inadequate blood clotting. Overactive blood clotting is harmful because of the tendency for thrombus formation and occlusion of arteries and veins. Vessels may become directly blocked by the thrombus, or a portion of the thrombus may break off and create an embolism that lodges elsewhere in the vascular system. The tendency for excessive thrombus formation in the venous system is usually treated with anticoagulant drugs such as heparin and warfarin. Platelet inhibitors such as aspirin help prevent arterial thrombogenesis. Thrombolytic drugs (streptokinase, t-PA) that facilitate the dissolution of harmful clots may successfully reopen... 

Adenosine, in addition to serving as a substrate for the generation of cAMP plays a physiologic role as a platelet inhibitor and a vasodilator and may attenuate neutrophil-mediated damage to endothelial cells, Adenosine diphosphate (ADP)— a potent platelet agonist—is converted to adenosine, which is taken up rapidly by cells, especially erythrocytes and endothelial cells, A small proportion is metabolized to the aforementioned cyclic nucleotides. The remainder is broken down to inosine and subsequently to xanthine. Dipyridamole inhibits the active transport of adenosine into cells, but does not interfere with the passive diffusion. Since the platelet inhibitory effects of adenosine proceed via stimulation of adenylate cyclase, these effects can also be amplified by dipyridamole, In circulating blood, the largest amount of adenosine is found in red blood cells, This may, in part, help explain why dipyridamole is much more effective in whole blood than in plasma. 

ChesebroJH, Clementsw IP FusterV etal. A platelet-inhibitor drug trial in coronary-artery bypass operation Benefit of eariy perioperative dipyridamole and aspirin therapy on eariy postoperative vein-graft patency. N Engl J Med 1982 307 73-78. 

Wilhite DB, Comerota AJ, Schmieder FA, et al. Managing PAD with multiple platelet inhibitors The effect of combination therapy on bleeding time. J Vase Surg 2003 38 710-713. 

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