Orally Ingested Heparin Is Absorbed in, Humans

Abstract

It has been accepted for many years that orally ingested heparin is not absorbed. Recent evidence has shown that heparin placed in the stomach of rats is very rapidly absorbed and that it also quickly and almost completely attaches to the vascular endothelium and prevents jugular vein thrombosis. Within 6 min, heparin was undetectable in the blood plasma. If a similar situation exists in humans, blood samples taken >15 min after heparin ingestion will lack evidence of anticoagulant activity. In this study, 45 individuals swallowed 20,000 units of heparin. Plasma activated partial thromboplastin time (APTT) levels were determined (in duplicate) before and at frequent intervals for 30 min after the heparin ingestion. There as a slightly prolonged APTT (range, 1-5 s) after swallowing the heparin. The average increase in the APTT was 2.3 s, which is statistically significant (p < 0.001), as the standard deviation of the method is .43 s. In several instances, frozen plasma aliquots, analyzed for heparin by a chromogenic method, showed its presence after ingestion. The preliminary results are important, although obviously oral heparin does not attain effective anticoagulant levels, as the many non-anticoagulant actions of heparin and the observation of its absorption after oral ingestion present numerous possibilities for new clinical applications. Key Words: Heparin—Oral absorption.