Innohep (tinzaparin sodium) injectable

The following drug information is obtained from various newswires, published medical journal articles, and medical conference presentations.

Approval Status:

Approved July 2000

Specific Treatments:

Deep vein thrombosis with or without pulmonary embolism when administered in conjunction with warfarin sodium

General Information

Innohep (tinzaparin sodium) injectable formulation is indicated for the treatment of acute symptomatic deep vein thrombosis, with or without pulmonary embolism when administered in conjunction with warfarin sodium. It is available in a multiple dose 2mL vial, by prescription only.

Clinical Results

A randomized, multicenter, double-blind study of Innohep was held involving 435 hospitalized subjects with symptomatic, proximal DVT. Subjects ranged in age from 19 - 92 years, with the mean falling around 61 years of age. 55% were male and 88% were white, 8% were black. Innohep SC was administered to some subjects once daily according to body weight (175 IU/kg) along with a placebo IV bolus followed by continuous placebo IV infusion. Others were given unfractionated heparin as an initial IV bolus dose (5,000 IU) followed by continuous IV infusion of unfractionated heparin with the rate adjusted to the aPTT (1.5 to 2.5 times control value) and a once daily SC placebo injection. Subjects underwent treatment for 6 days and both groups also received oral warfarin sodium starting on Day 2 continuing to Day 90 with doses titrated to a target INR of 2.0 to 3.0. The 90 day cumulative thromboembolic (TE) rate (recurrent DVT or PT) was not significantly different than the rate with unfractionated heparin.

Side Effects

Innohep is contraindicated in patients who have a history of heparin-induced thrombocytopenia, patients with active bleeding and patients with hypersensitivity to tinzaparin sodium. Patients with a known sensitivity to heparin, sulfites, benzyl alcohol or pork products should not use Innohep.

Innohep is not intended for IV or IM administration.

Common side effects include, but are not limited to:

  • Bleeding
  • Thrombocytopenia
  • Mild local pain around injection site

There are many other precautions that should be considered before taking Innohep.

Nursing mothers should know that trace amounts of the drug were found in the milk of test animals. There have also been reports of fetal mortality/miscarriage in women who had high risk pregnancies and were taking Innohep. One incident each of Down's syndrome, optic nerve hypoplasia and cleft palate were reported by pregnant women taking Innohep. However, no conclusive studies have been done concerning a cause and effect relationship in these cases.

Mechanism of Action

Tinzaparin sodium is a low molecular weight heparin with antithombotic properties. Tinzaparin sodium inhibits reactions that lead to the clotting of blood including the formation of fibrin clots, both in vitro and in vivo. It acts as a potent co-inhibitor of several activated coagulation factors, especially factors Xa and Iia (thrombin). The primary inhibitory activity is mediated through the plasma protease inhibitor, antithrombin.

Bleeding time is usually unaffected by tinzaparin sodium. Activated partial thromboplastin time (aPTT) is prolonged by therapeutic doses of tinzaparin sodium used in the treatment of deep vein thrombosis (DVT). Prothrombin time (PT) may be slightly prolonged with tinzaparin sodium treatment but usually remains within the normal range. Neither aPTT nor PT can be used for therapeutic monitoring of tinzaparin sodium.

Neither unfractionated heparin nor tinzaparin sodium have intrinsic fibrinolytic activity; therefore, they do not lyse existing clots. Tinzaparin sodium induces release of tissue factor pathway inhibitor, which may contribute to the antithrombotic effect. Heparin is also known to have a variety of actions that are independent of its anticoagulant effects. These include interactions with endothelial cell growth factors, inhibition of smooth muscle cell proliferation, activation of lipoprotein lipase, suppression of aldosterone secretion, and induction of platelet aggregation. (From FDA Label)