Anticoagulants: A Comparison between Heparin and Warfarin
Posted 03-02-2009 at 09:42 AM by ladypam
Inside the body is a clotting mechanism composed of several clotting factors that is triggered whenever it detects an injury in the body. However, blood clots sometimes form because of an imbalance of these clotting factors or due to a clotting disorder. These blood clots can move about blood vessels and can eventually block its path, which can be quite fatal, especially when it occurs in the lungs. And this is where anticoagulants like heparin and warfarin come in.
Anticoagulants act on certain clotting factors in the coagulation cascade to prevent the formation of clots. They do not directly dissolve a present blood clot but act to reduce the formation of new ones.
Heparin
Heparin is a mucopolysaccharide that is naturally occurring in the body in mast cells and basophils although the commercial ones are extracted from porcine intestinal mucosa or bovine lung. It is found in varying sizes, depending on its affinity to coagulant proteins and its anticoagulant activity. It acts to increase the formation of complexes, whose action is to inhibit the formation of thrombin, which can activate the formation of a fibrin clot.
Heparin cannot be taken orally since certain substances found in the gastrointestinal tract may inactivate it. It is best taken intravenously or subcutaneously, since it is absorbed readily without inactivating it. Intramuscular administration is not done because of the risk of bleeding at the site.
Heparin is the first choice in anticoagulants because of the speed of its action, although it has a short duration, thus needing a continuous infusion to maintain its therapeutic levels. It is often used for patients with pulmonary emboli or in deep vein thrombosis. Low doses are often given for prevention while a higher one is given to those with deep venous thrombi. Patients receiving heparin are closely monitored for adverse effects that may arise during treatment. It has a half life of one hour, and an overdose is easily corrected through the cessation of administration as well as the giving of protamine sulfate which can neutralize heparin.
Heparin is safe for pregnant women although increases the risk for hemorrhagic complications in the elderly, alcoholics and people with clotting disorders. It may cause some allergic reactions on the site of injection, often due to impurities or preservatives in the heparin solution. Long term use of heparin may lead to osteoporosis.
Warfarin
Warfarin (Waran Coumadin, Marevan, and Jantoven), is a coumarin compound found accidentally in spoiled sweet clover hay when given to cattle. It was first modified for use as a rodent poison since it was thought to be too toxic for humans. However, it has evolved into being the medication of choice to maintain anticoagulation therapy in humans since it is easily absorbed in the gastrointestinal tract and retain its effect for 2 to 5 days.
Warfarin acts by inhibiting the action of vitamin K, thus interfering in the activation of certain clotting factors through to inhibit the clotting mechanism. It is also found to bind with plasma proteins thus other medications that have the same action may affect the efficacy of its therapy.
Warfarin is used with patients with pulmonary embolism, using artificial heart valves, and those who will undergo orthopedic surgery.
Warfarin is often used with heparin as its initial anticoagulant since its action will peak a few days after. Close monitoring and dosage control is needed with warfarin therapy since when an overdose occurs, with severe bleeding, the cessation of the medication is not enough to reverse the action. The reason for this is that warfarin is eliminated slowly, plus the fact that new clotting factors need time to be synthesized. Phytonadione which is a medication containing vitamin K may be administered although because of the risk of anaphylactic reactions with this medication, it is given only in very serious bleeding conditions.
Warfarin is also seen in to interact with several drugs, as compared with a few that interact with heparin. Warfarin may interact with some antibiotics, cholestyramine, aspirin, carbamazepine, Phenobarbital, ethyl alcohol, etc, that act to inhibit the action of warfarin. Warfarin is also not a safe drug to administer to pregnant women since it can cross the placenta and reach the baby.
Between heparin and warfarin, the choice of which anticoagulant to use will depend on the condition being treated as well as how the body reacts to the medication. Both have their own advantage and disadvantage, which is dependent on the physician’s diagnosis on which to prescribe. However, proper knowledge of its effects and administration can go a long way in preventing adverse reactions from occurring. It is always best to consult a doctor before taking any medication.
Anticoagulants act on certain clotting factors in the coagulation cascade to prevent the formation of clots. They do not directly dissolve a present blood clot but act to reduce the formation of new ones.
Heparin
Heparin is a mucopolysaccharide that is naturally occurring in the body in mast cells and basophils although the commercial ones are extracted from porcine intestinal mucosa or bovine lung. It is found in varying sizes, depending on its affinity to coagulant proteins and its anticoagulant activity. It acts to increase the formation of complexes, whose action is to inhibit the formation of thrombin, which can activate the formation of a fibrin clot.
Heparin cannot be taken orally since certain substances found in the gastrointestinal tract may inactivate it. It is best taken intravenously or subcutaneously, since it is absorbed readily without inactivating it. Intramuscular administration is not done because of the risk of bleeding at the site.
Heparin is the first choice in anticoagulants because of the speed of its action, although it has a short duration, thus needing a continuous infusion to maintain its therapeutic levels. It is often used for patients with pulmonary emboli or in deep vein thrombosis. Low doses are often given for prevention while a higher one is given to those with deep venous thrombi. Patients receiving heparin are closely monitored for adverse effects that may arise during treatment. It has a half life of one hour, and an overdose is easily corrected through the cessation of administration as well as the giving of protamine sulfate which can neutralize heparin.
Heparin is safe for pregnant women although increases the risk for hemorrhagic complications in the elderly, alcoholics and people with clotting disorders. It may cause some allergic reactions on the site of injection, often due to impurities or preservatives in the heparin solution. Long term use of heparin may lead to osteoporosis.
Warfarin
Warfarin (Waran Coumadin, Marevan, and Jantoven), is a coumarin compound found accidentally in spoiled sweet clover hay when given to cattle. It was first modified for use as a rodent poison since it was thought to be too toxic for humans. However, it has evolved into being the medication of choice to maintain anticoagulation therapy in humans since it is easily absorbed in the gastrointestinal tract and retain its effect for 2 to 5 days.
Warfarin acts by inhibiting the action of vitamin K, thus interfering in the activation of certain clotting factors through to inhibit the clotting mechanism. It is also found to bind with plasma proteins thus other medications that have the same action may affect the efficacy of its therapy.
Warfarin is used with patients with pulmonary embolism, using artificial heart valves, and those who will undergo orthopedic surgery.
Warfarin is often used with heparin as its initial anticoagulant since its action will peak a few days after. Close monitoring and dosage control is needed with warfarin therapy since when an overdose occurs, with severe bleeding, the cessation of the medication is not enough to reverse the action. The reason for this is that warfarin is eliminated slowly, plus the fact that new clotting factors need time to be synthesized. Phytonadione which is a medication containing vitamin K may be administered although because of the risk of anaphylactic reactions with this medication, it is given only in very serious bleeding conditions.
Warfarin is also seen in to interact with several drugs, as compared with a few that interact with heparin. Warfarin may interact with some antibiotics, cholestyramine, aspirin, carbamazepine, Phenobarbital, ethyl alcohol, etc, that act to inhibit the action of warfarin. Warfarin is also not a safe drug to administer to pregnant women since it can cross the placenta and reach the baby.
Between heparin and warfarin, the choice of which anticoagulant to use will depend on the condition being treated as well as how the body reacts to the medication. Both have their own advantage and disadvantage, which is dependent on the physician’s diagnosis on which to prescribe. However, proper knowledge of its effects and administration can go a long way in preventing adverse reactions from occurring. It is always best to consult a doctor before taking any medication.
Total Comments 0
