Heparin is an anticoagulant produced naturally in the lungs and liver. It may be administered as a medication to address blood clotting disorders such as thrombosis, typically in a hospital setting. This drug can be extremely dangerous if it is used improperly or without supervision, and a number of precautions need to be observed when administering heparin to ensure that the drug does not cause complications in the patient.

The heparin used as a drug is extracted from pigs and cows. It is among a class of drugs known as blood thinners. In the case of heparin, the drug inhibits clotting. While it cannot dissolve clots, it can prevent the formation of clots, and it will keep existing clots from getting any larger. The drug can be used to treat a range of clotting disorders.

Surgeons may administer heparin during surgery to prevent clotting, and the drug can also be given to people with intravenous catheters and other medical devices which could contribute to the development of clots. People with specific clotting disorders may be prescribed heparin to address these disorders. The drug is typically delivered by injection in a sodium chloride solution.

If someone takes too much of this drug, it can cause fatal hemorrhage and other bleeding problems. Many people on the drug experience “bleeding events,” in which a small cut or an event like a menstrual period results in a much more blood than normal. Irritation around the injection site is common, and some people develop hypersensitivity to textures and temperature changes while on heparin.

Studies on pregnant women seem to suggest that the drug is not immediately dangerous to the fetus, and when an anticoagulant is needed, heparin may be recommended in lieu of more dangerous drugs. However, an increased rate of miscarriage has been reported for women on the drug, although the medical community is not sure about whether this is caused by the drug, or by the underlying medical conditions leading to the need for heparin. The drug also appears to be safe for use while breastfeeding, although additional research is needed.

Heparin can cross-react with a number of drugs, from aspirin to herbal medicine. It's important for patients to disclose all of the drugs they are using, prescription or not, so that the doctor can confirm that a cross-reaction will not occur. The drug can also be dangerous for people who have recently fallen, along with people who suffer from certain illnesses.