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Biomedical subjects

Alexander G G Turpie

Publications and source records attributed to Alexander G G Turpie.

49 records · Page 3Linked to original sources
PubMed2002

Postoperative fondaparinux versus preoperative enoxaparin for prevention of venous thromboembolism in elective hip-replacement surgery: a randomised double-blind comparison.

BACKGROUND: Despite use of thromboprophylaxis, elective hip-replacement surgery carries a high risk of venous thromboembolic complications. We aimed to assess the ability of the pentasaccharide fondaparinux, the first of a new class of synthetic antithrombotic agents, to further reduce this risk. METHODS: In a double-blind study, we randomly assigned 2309 consecutive patients aged 18 years or older who were undergoing elective hip-replacement surgery to once daily, subcutaneous injections of either 2.5 mg fondaparinux, starting postoperatively, or 40 mg enoxaparin, starting preoperatively. The primary efficacy outcome was venous thromboembolism up to day 11, defined as deep-vein thrombosis detected by mandatory bilateral venography, documented symptomatic deep-vein thrombosis, or documented symptomatic pulmonary embolism. The main safety outcomes were bleeding and death. The duration of follow-up was 6 weeks. Analysis was per protocol. FINDINGS: We assessed the primary efficacy outcome in 1827 (79%) of 2309 patients. By day 11, venous thromboembolisms were recorded in 37 (4%) of 908 patients assigned to fondaparinux and in 85 (9%) of 919 assigned to enoxaparin (difference -5.2% [95% CI -8.1 to -2.7], p<0.0001). The relative reduction in risk was 55.9% (95% CI 33.1-72.8). The two groups did not differ in frequency of death or clinically relevant bleeding. INTERPRETATION: Drugs that act through specific inhibition of factor Xa, such as fondaparinux, could be more effective than low molecular weight heparins in prevention of venous thromboembolism in patients undergoing hip-replacement surgery.

Adult↗
PubMed2002

Pentasaccharides.

Fondaparinux sodium is the first in a new class of antithrombotic agents possessing selective inhibitory activity against factor Xa. The agent was designed and developed with the objective of overcoming the limitations of currently available therapies for the prevention and treatment of venous and arterial thromboembolic disease. Extensive data from preclinical and clinical trials demonstrate fondaparinux's favorable pharmacokinetic profile combined with promising efficacy and safety results in the prevention of venous thromboembolism following major orthopedic surgery, in the treatment of deep venous thrombosis, and in acute coronary syndromes.

Animals↗
PubMed2002

Optimizing prophylaxis of venous thromboembolism.

Thrombotic events contribute significantly to the morbidity, mortality, and health care costs of patients undergoing major orthopedic surgery. Despite therapy with unfractionated heparin, low-molecular-weight heparin, or warfarin, thrombotic events continue to occur at an unacceptably high rate in populations at risk. The need for improved prophylaxis against venous thromboembolism has resulted in the development of several new antithrombotics, both recently approved and investigational, that target specific steps in the hemostatic pathway. These include direct thrombin inhibitors, agents that inhibit the factor VIIa-tissue factor complex, and selective factor Xa inhibitors. Fondaparinux is the first of the selective factor Xa inhibitors. It was evaluated in the most comprehensive drug development program ever in major orthopedic surgery, culminating in four phase III trials involving more than 7000 enrollees, and is the first agent in its class to be approved by the U.S. Food and Drug Administration and the European Agency for the Evaluation of Medicinal Products. It has been suggested that fondaparinux's superior efficacy may be related to its ability to initiate selective inhibition of factor Xa and its predictable linear pharmacokinetics.

Arthroplasty, Replacement↗
PubMed2002

State of the art--a journey through the world of antithrombotic therapy.

The introduction of low-molecular-weight heparins (LMWHs) has contributed to major improvements in the management of venous thromboembolism (VTE). The LMWHs have been shown to be as effective as, and safer than, unfractionated heparin (UFH) in the prevention and treatment of VTE, and their use is included as a grade 1A recommendation in the Sixth American College of Chest Physicians Guidelines. Important practical disadvantages of treatment with UFH are the need for extended hospital stays and frequent monitoring of coagulation levels. In comparison, LMWHs offer convenient and cost-effective prophylaxis and treatment of VTE on an outpatient basis. The LMWHs have also had a major impact on the management of arterial thromboembolism. In patients with acute coronary syndromes (unstable angina and non-ST-segment elevation myocardial infarction), enoxaparin has demonstrated sustained clinical improvements in major ischemic outcomes compared with UFH. Antiplatelet agents have also contributed significantly to the development of effective antithrombotic therapy. Aspirin is the best known antiplatelet agent and has heretofore been the mainstay of antiplatelet therapy in unstable angina. New data indicate that combination therapy with aspirin and a novel thienopyridine, clopidogrel, may further improve outcomes in this indication.

Ambulatory Care↗
PubMed2002

Factor Xa inhibition in the prevention of venous thromboembolism and treatment of patients with venous thromboembolism.

Venous thromboembolism (VTE) is a life-threatening complication following orthopedic surgery. Selective factor Xa inhibition is a new antithrombotic approach designed to avoid difficulties associated with heparins and other current anticoagulants. Several antifactor Xa compounds are in early investigation, but fondaparinux (Arixtra; NV Organon, Oss, The Netherlands; Sanofi-Synthelabo, Paris, France) is the first and most advanced compound in the development of a new class of synthetic antithrombotic agents--the selective factor Xa inhibitors. Fondaparinux has a highly favorable pharmacokinetic profile; four large phase 3 trials comparing subcutaneous fondaparinux 2.5 mg once daily with the low molecular weight heparin (LMWH) enoxaparin in doses approved by regulatory bodies showed that fondaparinux reduced the overall risk of VTE in major orthopedic surgery by > 50% without increasing clinically relevant bleeding. Fondaparinux also appears to be a very promising candidate for the treatment of patients with existing VTE.

Animals↗
PubMed2002

Review of enoxaparin and its clinical applications in venous and arterial thromboembolism.

Venous and arterial thromboembolic disorders are common medical conditions that are associated with considerable morbidity and mortality. Unfractionated heparin (UFH) and its derivatives, the low molecular weight heparins (LMWHs), are the anticoagulants of choice when a rapid anticoagulant effect is required. LMWHs have several advantages over UFH, including a longer plasma half-life and higher bioavailability; a predictable dose response, which enables once- or twice-daily dosing; and a more convenient route of administration (subcutaneous instead of intravenous), which enables patients to self-inject in an out-patient setting. Enoxaparin is a LMWH prepared by alkaline hydrolysis of the benzylin ester of UFH. The efficacy of enoxaparin in the management of venous and arterial thromboembolism has been shown in a wide range of patient groups using doses ranging from fixed doses of 20 - 60 mg o.d. and 0.75 - 1.5 mg/kg b.i.d. Other doses, such as 80 mg/day for pregnant women with combined thrombophilic defects, have also been studied. The use of subcutaneous enoxaparin as an effective and safe home treatment for patients with acute proximal deep vein thrombosis (DVT) has been demonstrated. The benefits of preventing venous thromboembolic events with enoxaparin include reducing the costs associated with investigating the symptoms of DVT, acute treatment and hospitalisation, and potentially the development of post-thrombotic syndrome, while improving quality of life and so making the treatment cost effective. In contrast to other LMWHs, enoxaparin has been shown to provide better outcomes than UFH in the treatment of unstable angina and non-ST-segment elevation myocardial infarction, without increasing major bleeding. Adverse events with enoxaparin are infrequent; the most common events are minor bleeding complications. It should be noted that different doses or indications are approved in each country.

Anticoagulants↗
PubMed2002

Use of selective factor Xa inhibitors in special populations.

Many clinicians recommend long-term, postoperative thromboprophylaxis for patients who undergo major hip or knee replacement or hip fracture surgery. However, special care must be taken when administering pharmacoprophylaxis to such patients, as they commonly exhibit characteristics that are different from those of the general population and can affect their responses to certain drugs. Among the currently available thromboprophylactic agents are warfarin, the heparins, and the recently introduced selective factor Xa inhibitor, fondaparinux. One feature of fondaparinux is that it can be administered safely and efficaciously in a wide variety of patient populations, without the need for dosage modification.

Adult↗
PubMed2002

A meta-analysis of fondaparinux versus enoxaparin in the prevention of venous thromboembolism after major orthopaedic surgery.

A worldwide phase III program, consisting of four randomized, double-blind trials in patients undergoing surgery for hip fracture, in elective hip replacement surgery patients and in elective major knee surgery patients, was conducted to compare the benefit-to-risk ratio of a subcutaneous 2.5-mg once-daily regimen of fondaparinux, a synthetic selective factor Xa inhibitor, starting postoperatively with enoxaparin in preventing venous thromboembolism. The overall incidence of venous thromboembolism up to day 11 was reduced from 13.7% in the enoxaparin group to 6.8% in the fondaparinux group with a common odds reduction of 55.2% in favor of fondaparinux (95% confidence interval: 45.8-63.1%, p = 10(-17)). This superior efficacy of fondaparinux was also demonstrated for proximal deep vein thrombosis with a reduction of 57.4%. The overall incidence of clinically relevant bleeding was low and did not differ between the two groups. The benefit of fondaparinux was consistent across all types of surgery and all subgroups.

Adolescent↗
PubMed2002

A new antithrombotic strategy, the selective inhibition of coagulation factors, and its importance to the orthopedic specialist.

Traditional anticoagulant drugs including vitamin K antagonists and heparins have several limitations. Despite their use, the burden of venous thromboembolism remains high, particularly in patients undergoing major orthopedic surgery. A new strategy for the design of new antithrombotic drugs is based on selective inhibition of a specific coagulation factor. Fondaparinux is a synthetic selective inhibitor of factor Xa, which is critically positioned at the start of the common pathway of the coagulation system. Its pharmacokinetic profile allows for once-daily administration without the need for laboratory monitoring or dose adjustment. Fondaparinux has demonstrated its efficacy compared to a widely used low-molecular-weight heparin in a number of thromboprophylaxis trials after major orthopedic surgery and is approved for use in this setting.

Anticoagulants↗
PubMedDate not supplied

Fondaparinux.

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Biological Availability↗