Interesting Facts About Heparin

Heparin is a medication that prevents blood clotting. Where does heparin come from? It usually comes from bovine (cow) lungs or pig intestinal mucosa. Heparin is another example of a pharmacognosy drug since it comes from natural sources.

Heparin is a naturally occurring substance that our bodies produce to prevent clotting. Heparin allows our lungs to transfer oxygen to our blood. When blood is exposed to air it clots so heparin allows the blood to come in direct contact with the air we breath without clotting. 

Heparin is also present in our intestines. Digested food and the various enzymes that are present in our intestines also cause the blood to clot. Heparin also allows the blood in our intestines to absorb nutrients without clotting.



The following information is taken from Wood - Osol United States Dispensatory 23rd Edition 1943

In 1916 Howell and Holt prepared from the liver a material, which they called heparin, that had the power of preventing coagulation of the blood. Because of various impurities, however, it was not suited for medicinal use. The active principle was first separated by Schmitz and Fischer and almost simultaneously by Charles and Scott. According to Jorpes (Biochem. J., 1935, 29, 1817), it is a polysulfuric ester of mucoitin (which is one of the glucoproteins).

Reinert and Winterstein (A. L P., 1939, 62, 47) have found that the pure substance is of very low toxicity and does not cause anaphylaxis. According to Brinkhous and associates (Science, 1939, 90, 539) the anticoagulant effect of heparin depends upon a combination with some unknown factor of the blood which combination .prevents the change of prothrombin into thrombin. Murray and Best (Ann. Surg., 1938, 108, 163) report that heparin rapidly disappears from the bloodstream so that clotting time returns to normal within an hour or an hour and a half. The slow clotting time, however, can be indefinitely maintained by repeated injections.

The most frequent use of heparin has probably been to prevent post-operative thrombi, but it is also widely employed to lessen the coagulability of the blood in a variety of other circumstances. Sappington (J. A. M. A., 1939, 113, 22) suggests that in transfusions of blood the donor be given heparin to prevent clotting. Kelson (J. A. M. A., 1939, 113, 1700) has employed continuous injections of heparin in the treatment of streptococcus endocarditis for the purpose of preventing thrombotic deposition. Several units of dosage have been suggested: that of Charles is the anticoagulant activity of Mooth of a mg. of the barium salt; that of Hedenius is the quantity required to prevent the clotting of 1 cc. of cat's blood under standard conditions for 24 hours; that of Reinert and Winterstein is the amount which will prevent clotting of 1 cc. of cattle plasma for one hour. In the practical use it is desirable that the normal clotting time be determined before administration. In Sappington's experiments 1 mg. per kilo of body weight greatly slowed clotting.
In view of the variety of units employed the physician should be guided in dosage by the statements on the label of the various brands.

Liquaemin is the proprietary name of a standardized solution of heparin.