Heparin

Heparin, also known as unfractionated heparin (UFH), is a medication and naturally occurring glycosaminoglycan. As a medication it is used as an anticoagulant (blood thinner). Specifically it is also used in the treatment of heart attacks and unstable angina. It is given by injection into a vein or under the skin. Other uses include inside test tubes and kidney dialysis machines. Heparin, also known as unfractionated heparin (UFH), is a medication and naturally occurring glycosaminoglycan. As a medication it is used as an anticoagulant (blood thinner). Specifically it is also used in the treatment of heart attacks and unstable angina. It is given by injection into a vein or under the skin. Other uses include inside test tubes and kidney dialysis machines. Common side effects include bleeding, pain at the injection site, and low blood platelets. Serious side effects include heparin-induced thrombocytopenia. Greater care is needed in those with poor kidney function. Heparin appears to be relatively safe for use during pregnancy and breastfeeding. Heparin is produced by basophils and mast cells in all mammals. The discovery of heparin was announced in 1916. It is on the World Health Organization's List of Essential Medicines, the most effective and safe medicines needed in a health system. The wholesale cost in the developing world, when used for prevention, is about US$9.63–37.95 per month. In the United States it costs about $25–50 per month. A fractionated version of heparin, known as low molecular weight heparin, is also available. 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 formed. Heparin is generally used for anticoagulation for the following conditions: Heparin and its low-molecular-weight derivatives (e.g., enoxaparin, dalteparin, tinzaparin) are effective in preventing deep vein thromboses and pulmonary emboli in people at risk, but no evidence indicates any one is more effective than the other in preventing mortality. A serious side-effect of heparin is heparin-induced thrombocytopenia (HIT), caused by an immunological reaction that makes platelets a target of immunological response, resulting in the degradation of platelets, which causes thrombocytopenia. This condition is usually reversed on discontinuation, and in general can be avoided with the use of synthetic heparins. Also, a benign form of thrombocytopenia is associated with early heparin use, which resolves without stopping heparin. Two non-hemorrhagic side-effects of heparin treatment are known. The first is elevation of serum aminotransferase levels, which has been reported in as many as 80% of patients receiving heparin. This abnormality is not associated with liver dysfunction, and it disappears after the drug is discontinued. The other complication is hyperkalemia, which occurs in 5 to 10% of patients receiving heparin, and is the result of heparin-induced aldosterone suppression. The hyperkalemia can appear within a few days after the onset of heparin therapy. More rarely, the side-effects alopecia and osteoporosis can occur with chronic use. As with many drugs, overdoses of heparin can be fatal. In September 2006, heparin received worldwide publicity when three prematurely born infants died after they were mistakenly given overdoses of heparin at an Indianapolis hospital. Heparin is contraindicated in those with risk of bleeding (especially in people with uncontrolled blood pressure, liver disease, and stroke), severe liver disease, or severe hypertension.