Reviparin is an antithrombotic and belongs to the group of low molecular weight heparins (LMWH). Reviparin is an antithrombotic and belongs to the group of low molecular weight heparins (LMWH). Reviparin is a low molecular weight heparin obtained by nitrous acid depolymerization of heparin extracted from porcine intestinal mucosa. Its structure is characterized, for the most part, by a group of 2-O-sulfo-α-lidopyranosuronic acid. The average molecular weight is about 3900 daltons.