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  • ساعدوني في الحل

    السلام عليكم

    عندي سؤال وأتمنى أن تساعدوني في حله
    السؤال هو:
    compare between heparin and warvrin?
    أتمنى أن تكون الإجابة بالإنقلش
    شاكرة لكم ذلك

  • #2
    السلام عليكم ورحمة الله وبركاته

    اختى طالبة مختبرات دى بعض المعلومات واتمنى تفيدك

    Warfarin is an anticoagulant medication that is administered orally or, very rarely, by injection. It is also used as a pesticide against rats and mice.
    Warfarin inhibits the synthesis of biologically active forms of the vitamin K–dependent clotting factors II, VII, IX and X, as well as the regulatory factors protein C, protein S, and protein Z. Other proteins not involved in blood clotting, such as osteocalcin, or matrix Gla protein, may also be affected.

    The initial effect of warfarin administration is to briefly promote clot formation. This is because the level of protein S is also dependent on vitamin K activity. Reduced levels of protein S lead to a reduction in activity of protein C (for which it is the co-factor) and therefore reduced degradation of factor Va and factor VIIIa. This then causes the hemostasis system to be temporarily biased towards thrombus formation, leading to a prothrombotic state. This is one of the benefits of co-administering heparin, an anticoagulant that acts upon antithrombin and helps reduce the risk of thrombosis, which is common practice in settings where warfarin is loaded rapidly.


    [edit] Uses

    [edit] Medical use
    Warfarin is prescribed to people with an increased tendency for thrombosis or as prophylaxis in those individuals that have already formed a blood clot (thrombus), which required treatment. This can help prevent formation of future blood clots and help reduce the risk of embolism (migration of a thrombus to a spot where it blocks blood supply to a vital organ). Common clinical indications for warfarin use are atrial fibrillation, artificial heart valves, deep venous thrombosis, pulmonary embolism, antiphospholipid syndrome and occasionally after myocardial infarction.[5]

    Dosing of warfarin is complicated by the fact that it is known to interact with many commonly-used medications and other chemicals that may be present in appreciable quantities in food. These interactions may enhance or reduce warfarin's anticoagulation effect. Many commonly-used antibiotics, such as metronidazole or the macrolides, will greatly increase the effect of warfarin by reducing the metabolism of warfarin in the body. Other broad-spectrum antibiotics can reduce the amount of the normal bacterial flora in the bowel, which make significant quantities of Vitamin K, thus potentiating the effect of warfarin. In addition, food that contains large quantities of Vitamin K will reduce the warfarin effect; and medical conditions such as hypo- or hyperthyroidism will alter the rate of breakdown of the clotting factors
    The only common side-effect of warfarin is hemorrhage (bleeding). The risk of severe bleeding is small but definite (1-2% annually) and any benefit needs to outweigh this risk when warfarin is considered as a therapeutic measure. Risk of bleeding is augmented if the INR is out of range (due to accidental or deliberate overdose or due to interactions), and may cause hemoptysis (coughing up blood), excessive bruising, bleeding from nose or gums, or blood in urine or stool.

    The risks of bleeding is increased when warfarin is combined with antiplatelet drugs such as clopidogrel, aspirin, or nonsteroidal anti-inflammatory drugs.[6] The risk may also be also increased elderly patients[7] and in patients on hemodialysis
    warfarin necrosis, which occurs more frequently shortly after commencing treatment in patients with a deficiency of protein C
    warfarin could reduce bone mineral density
    Heparin is widely used as an injectable anticoagulant as it is degraded when taken by mouth .it is a naturally-occurring anticoagulant produced by basophils and mast cells.[6] Heparin acts as an anticoagulant, preventing the formation of clots and extension of existing clots within the blood. While heparin does not break down clots that have already formed (unlike tissue plasminogen activator), it allows the body's natural clot lysis mechanisms to work normally to break down clots that have already formed. Heparin is used for anticoagulation for the following conditions:

    Acute coronary syndrome, e.g., myocardial infarction
    Atrial fibrillation
    Deep-vein thrombosis and pulmonary embolism
    Cardiopulmonary bypass for heart surgery.
    Heparin binds to the enzyme inhibitor antithrombin III (AT-III) causing a conformational change that results in its active site being exposed. The activated AT-III then inactivates thrombin and other proteases involved in blood clotting, most notably factor Xa. The rate of inactivation of these proteases by AT-III can increase by up to 1000-fold due to the binding of heparin.[9]

    AT-III binds to a specific pentasaccharide sulfation sequence contained within the heparin polymer
    The conformational change in AT-III on heparin-binding mediates its inhibition of factor Xa. For thrombin inhibition however, thrombin must also bind to the heparin polymer at a site proximal to the pentasaccharide. The highly-negative charge density of heparin contributes to its very strong electrostatic interaction with thrombin.[1] The formation of a ternary complex between AT-III, thrombin, and heparin results in the inactivation of thrombin


    http://www.circ.ahajournals.org/cgi/...full/116/5/552

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    • #3
      تسلمي أختي على المباذرة في مساعدتي
      وجزاك الله ألف خير وفرتي علي وقت كثير خصوصا إن هالأيام أوقات امتحانات

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