A decades-old form of the anticlotting drug heparin is as safe, as effective, and potentially as convenient to use as recent derivatives that are many times as expensive.
Some people who develop blood clots deep in leg veins receive plain heparin, which can prevent subsequent, sometimes-deadly clots. Others get low-molecular-weight heparin, which comes in several varieties and is sold by various manufacturers.
Doctors usually administer the plain heparin by intravenous drip, which requires hospitalization. IV administration enables a physician to quickly adjust a patient's dose if, for example, testing suggests that the person's blood remains excessively prone to clotting.
Low-molecular-weight heparin was designed to behave more predictably in the body, thereby making monitoring unnecessary. Patients are sent home with the drug in syringes that they can use to inject themselves once or twice a day.