Heparin and Lovenox® are two anticoagulant drugs commonly used to assist in preventing blood clots from forming, or to slow down how quickly they form. They are also often used to dissolve existing clots and restore normal blood flow. The essential difference between the two is that they have different molecular weights, which causes them to behave differently in use.
Heparin is a naturally occurring substance that is found in human liver and lung tissue. It assists in the continued smooth flow of blood through those organs. The heparin that is used for medical treatment is not derived from human tissue, but is instead made from either the intestines of pigs or from the lung tissue of cattle. In use, these forms of derived heparin are indistinguishable from human heparin. When injected, heparin works to dissolve or prevent clots for several hours.
Lovenox® is derived from heparin. The difference is that it has been altered in such a way that is has a lower molecular weight than heparin. This change in structure allows Lovenox® to last much longer than heparin, as much as 24 hours, making it much more effective in some situations.
Despite the fact that heparin and Lovenox® serve essentially the same purpose, they are used in different situations. Heparin is indicated any time a patient is at risk for forming a blood clot having to do with any use of intravenous (IV) drugs, dialysis or chemotherapy and it can be given long-term, over a period of months or even years. Lovenox®, on the other hand, is the drug of choice when there is concern about clotting problems related to surgery, and is not to be administered longer than 17 days. It is also used as a treatment for deep vein thrombosis (DVT) and pulmonary embolisms. If a patient is moving from injections to oral anticoagulants, Lovenox® is used as part of the transition.
When heparin and Lovenox® are administered, heparin can be given either intravenously or subcutaneously — under the skin. Lovenox® is only injected subcutaneously. Frequent monitoring of blood clotting ability is required when the patient is using heparin, but with Lovenox® the monitoring can be much less frequent. How often the patient is monitored depends on the patient’s condition and the dosage of either heparin or Lovenox® being administered. Whichever drug is chosen, both heparin and Lovenox® can be life saving when used properly.