An equivalence study of two low-molecular-weight heparins in the prevention and treatment of deep-vein thrombosis after total hip replacement

Tinzaparin sodium: a review of its use in the prevention and treatment of deep vein thrombosis and pulmonary embolism, and in the prevention of clotting in the extracorporeal circuit during haemodialysis

Tinzaparin sodium (Innohep) is a low molecular weight heparin (LMWH) that is effective in the prevention and treatment of deep vein thrombosis (DVT) and/or pulmonary embolism (PE), and in maintaining the patency of haemodialysis circuits in adult patients. In terms of preventing DVT and/or PE, therapy with subcutaneous tinzaparin sodium was more effective than oral warfarin and equivalent to subcutaneous enoxaparin sodium in patients undergoing orthopaedic surgery, and did not significantly differ from that of subcutaneous unfractionated heparin (UFH) in patients undergoing general surgery. In the initial therapy of adult patients with DVT and/or PE, subcutaneous tinzaparin sodium was at least as effective as intravenous UFH and did not significantly differ from subcutaneous dalteparin sodium. Various other studies have demonstrated that the long-term efficacy of subcutaneous tinzaparin sodium in the treatment of patients with DVT and/or PE was sustained for a total period of up to 12 months. Tinzaparin sodium was also demonstrated to be effective in maintaining the patency of haemodialysis circuits in adult patients with end-stage renal failure. In clinical studies, tinzaparin sodium was generally well tolerated in the prevention and treatment of DVT and/or PE in adult patients, including in elderly patients, and in patients undergoing haemodialysis. As expected, bleeding complications were the most frequently occurring adverse event. Thus, available data indicate that tinzaparin sodium is a useful option in the prevention and treatment of DVT and/or PE, and in maintaining the patency of haemodialysis circuits in adult patients.

Direct comparison of enoxaparin and nadroparin in a rabbit model of arterial thrombosis prevention

INTRODUCTION

The aim of the study was to evaluate and compare the efficacy of standard unfractionated heparin (UFH) and low-molecular weight heparins (LMWH's).

MATERIALS AND METHODS

We modified a previously published rabbit model of arterial thrombosis prevention [1,2] to compare unfractionated heparin and two different doses of two low-molecular weight heparin fragments--nadroparin and enoxaparin. Thrombosis in the distal aorta was triggered by vessel wall injury and critical stenosis. Blood flow in the damaged arterial segment was monitored by a flow probe placed distal to the constrictor. The primary endpoints of the study were: (1) cumulative flow, (2) time to occlusion and (3) residual clot weight. Thirty six animals were split into 6 groups with six animals in each group. Control groups were given saline or heparin and four more groups were used to compare LMWH's at 2 different doses.

RESULTS

In our study, all treatments were superior to the saline control group (alpha<or=0,01). Standard heparin was inferior (alpha<or=0,05) to both low molecular weight heparins for all primary endpoints (cumulative flow, time to occlusion and residual clot weight). There were no differences between the LMWH's except for cumulative flow at high doses.

CONCLUSIONS

This study revealed no relevant differences between nadroparin and enoxaparin for the primary endpoints of our model. Clinical use of each drug remains a personal preference.

Evaluation of the Effectiveness and Safety of Bemiparin in a Large Population of Orthopedic Patients in a Normal Clinical Practice

The authors conducted a prospective, open, multicenter, observational study to audit the utilization patterns of bemiparin in orthopedic patients in daily clinical practice. They analyzed rates of documented symptomatic venous thromboembolism (VTE) (deep vein thrombosis and pulmonary embolism) confirmed by objective methods, major bleeding, death, thrombocytopenia, and other adverse events. It was also intended to analyze the influence of concomitant factors (bemiparin dose, concomitant medications, age, and obesity) on VTE and bleeding rates. A total of 7959 patients were included and received bemiparin for 28 days (median). Bemiparin 3500 IU/d was used in 84.9% of patients, whereas bemiparin 2500 IU/d was administered to 15.1% of patients. Reason for prophylaxis (number of cases [%]) included cast immobilization of the leg (2052 [25.8%]), knee replacement (1082 [13.6%]), hip replacement (876 [11.0%]), hip fracture surgery (437 [5.5%]), other lower limb surgery (1569 [19.7%]), knee arthroscopy (769 [9.7%]), and spine surgery (231 [2.9%]). A total of 943 patients with insufficient data on reason for prophylaxis and 560 patients with no outcome assessment were excluded from the analysis of clinical outcomes. Among 6456 assessable patients, the authors found a low rate of documented symptomatic VTE (0.91%), major bleeding (0.17%), deaths (0.37%), and mild to moderate thrombocytopenia (0.51%). None of the major bleedings was fatal or occurred in a critical organ. There were 3 deaths in which fatal pulmonary embolism (PE) could not be ruled out. There were no cases of severe type-II thrombocytopenia. VTE rates were not increased in obese patients, and major bleeding rates were not increased in elderly patients or in patients taking nonsteroidal anti-inflammatory drugs. In conclusion, bemiparin prophylaxis, given for 3 to 4 weeks in cast immobilization of the leg and other orthopedic procedures, was associated with low rates of VTE, bleeding, and other adverse events in normal clinical practice.

Tinzaparin: considerations for use in clinical practice

OBJECTIVE

To evaluate the safety and effectiveness of tinzaparin for the prevention and treatment of venous thromboembolism (VTE).

DATA SOURCES

A MEDLINE and PubMed database search (1980-December 2002) was conducted. Only articles written in English were reviewed.

STUDY SELECTION AND DATA EXTRACTION

Articles reporting the safety, efficacy, and cost-effectiveness of tinzaparin in humans were evaluated. Emphasis was placed on randomized, controlled trials.

DATA SYNTHESIS

Tinzaparin sodium is a low-molecular-weight heparin (LMWH) that exerts its anticoagulant effect through inhibition of factors Xa and IIa and release of tissue factor pathway inhibitor from the vascular epithelium. Tinzaparin is indicated for treatment of acute symptomatic deep-vein thrombosis (DVT), with or without pulmonary embolism. Clinical studies suggest that tinzaparin is also effective for VTE prophylaxis, as well as other indications. Once-daily subcutaneous tinzaparin is equally or more effective than intravenous unfractionated heparin (UFH) for prevention and treatment of VTE, at least as safe as UFH for bleeding complications, and requires little or no monitoring. No dose "cap" is required for obese patients, and no initial dosing adjustments are necessary in elderly and/or renally impaired patients, although some monitoring is recommended. The few comparative data available suggest that tinzaparin efficacy may be comparable to that of other LMWHs; more comparative studies are needed. Pharmacoeconomic studies indicate a favorable cost-benefit ratio.

CONCLUSIONS

Tinzaparin is safe and effective for prevention and treatment of DVT. Consistent once-daily dosing may facilitate self-administration of tinzaparin in the outpatient setting.

Tinzaparin

Low-molecular-weight heparins (LMWH) are efficacious agents that offer clinical and pharmacoeconomic advantages over unfractionated heparin (UFH) for the treatment of ACS and venous thromboembolism. Tinzaparin is a LMWH approved for the treatment of deep venous thrombosis with and without pulmonary embolism, when used in conjunction with warfarin. In studies with hospitalized patients who had deep venous thrombosis or pulmonary embolism, tinzaparin was at least as efficacious as UFH, with fewer adverse bleeding events. It is also efficacious for thromboembolic prophylaxis in patients undergoing general and orthopedic surgery. Studies have shown that tinzaparin is at least as effective as UFH for patients undergoing surgery and in other patients at risk for developing thromboembolism. It is currently not recommended for use in patients with ischemic strokes. There are minimal data available regarding its use in the management of patients with unstable angina (UA) and non-ST-segment elevation myocardial infarction.