Heparin sodium

Absorption

Subcutaneous injection - about 90% when measured as anti-Xa activity versus 67% for anti-IIa activity.

Toxicity

Osteoporosis with increasing duration of use, bleeding, alopecia, heparin induced thrombocytopenia (HIT). All of these adverse drug reactions occur less with LMWH compared to unfractionated heparin. Tinzaparin showed no toxic effects at doses up to 5 mg/kg in mice, rats, or dogs in standard acute, subacute, and chronic toxicity studies.

Description

Reviparin sodium, a second-generation low molecular weight heparin produced from porcine mucosal heparin, has been introduced for the prevention of deep vein thrombosis and pulmonary embolism following surgery. It has sustained activity and increased bioavailability over unfractioned heparin. More noticeably, reviparin shows a pronounced inhibitory effect, both in vitro and in vivo , on smooth muscle cell proliferation which plays a predominant role in restenosis following angioplasty. Indeed, a lower incidence of restenosis without major bleeding complications has been reported for reviparin treated patients who successfully underwent percutaneous transluminal coronary angioplasty.

The Uses of Heparin sodium

Heparin sodium salt is used as a blood anti-coagulant. It is also used as an effective inhibitor of mesenchymal cell proliferation. Further, it binds to antithrombin III, which inhibits coagulation proteases. It is used as a major component of serum free media for preventing cell aggregation. It is also used as an anti-cancer agent in in vitro cancer research.

Background

Tinzaparin is a low molecular weight heparin (LMWH), produced by enzymatic depolymerization of unfractionated heparin from porcine intestinal mucosa. It is a heterogeneous mixture of with an average molecular weight between 5500 and 7500 daltons. Tinzaparin is composed of molecules with and without a special site for high affinity binding to antithrombin III (ATIII). This complex greatly accelerates the inhibition of factor Xa. It is an anticoagulant and considered an antithrombotic. Tinzaparin must be given either subcutaneously or parenterally. LMWHs are less effective at inactivating factor IIa due to their shorter length compared to unfractionated heparin.

Background

Reviparin is a low molecular weight heparin which seems to have a better safety profile than unfractionated heparin. It is prepared from porcine intestinal mucosa by nitrous acid depolymerization. Reviparin has a molecular weight of 3.9 kDa. It was developed by Abbott laboratories and in 2009, reviparin presented an orphan drug designation by the FDA.

Indications

By the FDA, reviparin is indicated for the treatment of deep vein which may lead to pulmonary embolism in pediatric patients. It is also indicated for the long-term treatment of acute deep vein thrombosis with or without pulmonary embolism in pregnant patients.

Indications

Tinzaparin is used for the prevention of postoperative venous thromboembolism in patients undergoing orthopedic surgery and in patients undergoing general surgery who are at high risk of developing postoperative venous thromboembolism. It is also used for the treatment of deep vein thrombosis and/or pulmonary embolism. It is indicated for use in preventing clot formation in indwelling intravenous lines for hemodialysis.

What are the applications of Application

Heparin sodium salt is a heparin polymer that produces its anticoagulant effect by activating ATIII (antithrombin)

Pharmacokinetics

Tinzaparin, like other LMWHs, have a higher anti-Xa activity than anti-IIa activity. The anti-Xa activity of tinzaparin is 2.0 +/- 0.5 times greater than its to anti-IIa activity. Heparin exhibits approximately equal inhibitory activity against Xa and IIa. Tinzaparin is an anticoagulant that blocks the formation of thrombi. Like all LMWHs, tinzaparin only causes activated partial thromboplastin time (aPTT) prolongation at higher doses and routine monitoring is not recommended. However, anti-factor Xa levels may be monitored in some conditions such as pregnancy and renal dysfunction. Its use should be avoided in patients with a creatinine clearance less than 20 mL/min. In these patients, unfractionated heparin should be used. Tinzaparin can be used in patients who have a creatinine clearance between 20-30 mL/min, giving it the highest safety threshold for use in renal failure patients compared to all the LMWHs.

Pharmacokinetics

Reviparin is been shown to present significant inhibition of smooth muscle cell migration and proliferation in human cell cultures without affecting endothelial cell growth.

Metabolism

Not Available

Metabolism

Sulfation and polymerization occurs in the liver.