- Adverse effects
- Food Interactions
Unfractionated heparin (UH) is a heterogenous preparation of anionic, sulfated glycosaminoglycan polymers with weights ranging from 3000 to 30,000 Da. It is a naturally occurring anticoagulant released from mast cells. It binds reversibly to antithro...
Unfractionated heparin (UH) is a heterogenous preparation of anionic, sulfated glycosaminoglycan polymers with weights ranging from 3000 to 30,000 Da. It is a naturally occurring anticoagulant released from mast cells. It binds reversibly to antithrombin III (ATIII) and greatly accelerates the rate at which ATIII inactivates coagulation enzymes thrombin (factor IIa) and factor Xa. UH is different from low molecular weight heparin (LMWH) in the following ways: the average molecular weight of LMWH is about 4.5 kDa whereas it is 15 kDa for UH; UH requires continuous infusions; activated partial prothrombin time (aPTT) monitoring is required when using UH; and UH has a higher risk of bleeding and higher risk of osteoporosis in long term use. Unfractionated heparin is more specific than LMWH for thrombin. Furthermore, the effects of UH can typically be reversed by using protamine sulfate.Read more
Unfractionated heparin is indicated for prophylaxis and treatment of venous thrombosis and its exten... Unfractionated heparin is indicated for prophylaxis and treatment of venous thrombosis and its extension, prevention of post-operative deep venous thrombosis and pulmonary embolism and prevention of clotting in arterial and cardiac surgery. In cardiology, it is used to prevent embolisms in patients with atrial fibrillation and as an adjunct antithrombin therapy in patients with unstable angina and/or non-Q wave myocardial infarctions (i.e. non-ST elevated acute coronary artery syndrome) who are on platelet glycoprotein (IIb/IIIa) receptor inhibitors. Additionally, it is used to prevent clotting during dialysis and surgical procedures, maintain the patency of intravenous injection devices and prevent in vitro coagulation of blood transfusions and in blood samples drawn for laboratory values. Read more
Unfractionated heparin is a highly acidic mucopolysaccharide formed of equal parts of sulfated D-glu... Unfractionated heparin is a highly acidic mucopolysaccharide formed of equal parts of sulfated D-glucosamine and D-glucuronic acid with sulfaminic bridges. The molecular weight ranges from 3000 to 30,000 daltons. Heparin is obtained from liver, lung, mast cells, and other cells of vertebrates. Heparin is a well-known and commonly used anticoagulant which has antithrombotic properties. Heparin inhibits reactions that lead to the clotting of blood and the formation of fibrin clots both in vitro and in vivo. Small amounts of heparin in combination with antithrombin III, a heparin cofactor,) can inhibit thrombosis by inactivating Factor Xa and thrombin. Once active thrombosis has developed, larger amounts of heparin can inhibit further coagulation by inactivating thrombin and preventing the conversion of fibrinogen to fibrin. Heparin also prevents the formation of a stable fibrin clot by inhibiting the activation of the fibrin stabilizing factor. Heparin prolongs several coagulation tests. Of all the coagulation tests, activated partial prothrombin time (aPTT) is the most clinically important value. Read more
Mechanism of action
Under normal circumstances, antithrombin III (ATIII) inactivates thrombin (factor IIa) and factor Xa... Under normal circumstances, antithrombin III (ATIII) inactivates thrombin (factor IIa) and factor Xa. This process occurs at a slow rate. Administered heparin binds reversibly to ATIII and leads to almost instantaneous inactivation of factors IIa and Xa The heparin-ATIII complex can also inactivate factors IX, XI, XII and plasmin. The mechanism of action of heparin is ATIII-dependent. It acts mainly by accelerating the rate of the neutralization of certain activated coagulation factors by antithrombin, but other mechanisms may also be involved. The antithrombotic effect of heparin is well correlated to the inhibition of factor Xa. Heparin is not a thrombolytic or fibrinolytic. It prevents progression of existing clots by inhibiting further clotting. The lysis of existing clots relies on endogenous thrombolytics. Read more
Heparin must be given parenterally as it is not absorbed through the gastrointestinal mucosa. It is...
Heparin must be given parenterally as it is not absorbed through the gastrointestinal mucosa. It is usually given by iv infusion or deep sc injection. The onset of action is immediate after iv injection but can be delayed 20 to 60 minutes following sc injection.
Plasma heparin concentrations may be increased and activated partial thromboplastin times (aPTTs) may be more prolonged in geriatric adults (older than 60 years of age) compared with younger adults. Read more
Very high, mostly to low-density lipoproteins. It is also extensively bound by globulins and fibrino... Very high, mostly to low-density lipoproteins. It is also extensively bound by globulins and fibrinogens. Read more
Volume of distribution
40-70 mL/min (approximately the same as blood volume)Although heparin does not distribute into adipo... 40-70 mL/min (approximately the same as blood volume)Although heparin does not distribute into adipose tissues, clinicians should use actual body weight in obese patients to account for extra vasculature. Read more
Adult Clearance = 0.43 ml/kg/min25-28 weeks gestation = 1.49 ml/kg/min Adult Clearance = 0.43 ml/kg/min25-28 weeks gestation = 1.49 ml/kg/min
The plasma half-life of heparin increases from about 60 minutes with a 100 unit/kg do... 1.5 hours.
The plasma half-life of heparin increases from about 60 minutes with a 100 unit/kg dose to about 150 minutes with a 400 unit/kg dose. Read more
Route of elimination
The drug appears to be removed mainly by the reticuloendothelial system. A small fraction of unchang... The drug appears to be removed mainly by the reticuloendothelial system. A small fraction of unchanged heparin also appears to be excreted in urine. Heparin cannot be eliminated by hemodialysis. Read more
In mouse, the median lethal dose is greater than 5000 mg/kg. Another side effect is heparin-induced... In mouse, the median lethal dose is greater than 5000 mg/kg. Another side effect is heparin-induced thrombocytopenia (HIT syndrome). Platelet counts usually do not fall until between days 5 and 12 of heparin therapy. HIT is caused by an immunological reaction that makes platelets form clots within the blood vessels, thereby using up coagulation factors. It can progress to thrombotic complications such as arterial thrombosis, gangrene, stroke, myocardial infarction and disseminated intravascular coagulation. Symptoms of overdose may show excessive prolongation of aPTT or by bleeding, which may be internal or external, major or minor. Therapeutic doses of heparin give for at least 4 months have been associated with osteoporosis and spontaneous vertebral fractures. Osteoporosis may be reversible once heparin is discontinued. Although a causal relationship has not been established, administration of injections preserved with benzyl alcohol has been associated with toxicity in neonates. Toxicity appears to have resulted from administration of large amounts (i.e., about 100–400 mg/kg daily) of benzyl alcohol in these neonates. Its use is principally associated with the use of bacteriostatic 0.9% sodium chloride intravascular flush or endotracheal tube lavage solutions. Read more
|Effect||Regions||Age Groups||Incidences||Evidence Type|
|Itching and burning at the plantar site of feet||US||
|Nausea and vomiting||US||
|Suppression of aldosterone synthesis||US||
|Delayed transient alopecia||US||
|Episodes of painful, ischemic, and cyanosed limbs||US||
|Elevations of aminotransferase levels||US||
- Adequate calcium intake is recommended, needs increased with long term use, supplement recommended.
- Many herbs with anticoagulant properties (e.g. ginger, garlic, ginseng, green tea, evening primrose) may increase the risk of bleeding in patients on anticoagulant therapy such as heparin
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- 8 . Authors unspecified: Benzyl alcohol: toxic agent in neonatal units. Pediatrics. 1983 Sep;72(3):356-8. [PubMed: 6889041]
- 9 . Authors unspecified: Benzyl alcohol may be toxic to newborns. FDA Drug Bull. 1982 Aug;12(2):10-1. [PubMed: 7188569]
- 10 . Authors unspecified: Neonatal deaths associated with use of benzyl alcohol--United States. MMWR Morb Mortal Wkly Rep. 1982 Jun 11;31(22):290-1. [PubMed: 6810084]