Safety profile of tinzaparin administered once daily at a standard curative dose in two hundred very elderly patients

Use of Low-Molecular-Weight Heparin to Bridge Therapy in Obese Patients and in Patients with Renal Dysfunction

OBJECTIVE

To recommend strategies to bridge therapy with low-molecular-weight heparin (LMWH) in obese patients and in patients with renal dysfunction.

METHODS

A MEDLINE search was performed of the literature from January 1966-November 2005. Published material dealing with bridging of anticoagulation therapy or short-term use of LMWH therapy in patients with renal dysfunction or obesity was reviewed. The manufacturers of enoxaparin, dalteparin, and tinzaparin were contacted for the references used to determine dosing recommendations.

RESULTS

Although LMWH has been commonly used to bridge therapy, our search revealed no trials that specifically examined LMWH bridge therapy in obese patients or in patients with renal dysfunction. However, nine trials using LMWH in obese patients and 14 trials using LMWH in patients with renal dysfunction were identified. When compared with normal-weight individuals, obese patients receiving enoxaparin and dalteparin based on total body weight did not demonstrate higher hemorrhage rates or antifactor Xa levels. Subtherapeutic antifactor Xa levels were more common with once-daily dosing of enoxaparin than with dosing every 12 hours. Enoxaparin accumulates in patients with a creatinine clearance of 30 ml/minute or less; in this population, enoxaparin dosage adjustments have been attempted. Tinzaparin does not accumulate in patients with a creatinine clearance of 20 ml/minute or greater after at least 10 days of dosing.

CONCLUSION

Obese patients, weighing 90-150 kg, receiving LMWH for bridge therapy should receive dosages based on total body weight. Unfractionated heparin is recommended in patients weighing more than 150 kg; however, if LMWH is used, antifactor Xa levels should be monitored. Bridging with enoxaparin should be limited to patients with a creatinine clearance greater than 30 ml/minute. The use of enoxaparin 1 mg/kg once/day for patients with a creatinine clearance of 30 ml/minute or less is not recommended for anticoagulation bridge therapy. Tinzaparin may be considered for cross-coverage of high-risk patients with recent or recurrent venous thromboembolism who have a creatinine clearance of at least 20 ml/minute.

Anticoagulant Treatment of Deep Vein Thrombosis and Pulmonary Embolism

Venous thrombosis is a common disease. As the mean age of the population increases, so does the incidence of venous thromboembolism. Anticoagulant therapy is equally effective in young and older patients, and can reduce substantially the associated morbidity and mortality. When considering long-term oral anticoagulant therapy in older patients, however, careful ongoing evaluation is imperative to ensure that the risk of bleeding does not outweigh the antithrombotic benefits.

Thromboembolism and anticoagulant management in hemodialysis patients: A practical guide to clinical management

The need for anticoagulation in dialysis patients is common and the incidence of venous thromboembolism (VTE) and atrial fibrillation in this population is high. While direct data are lacking on the management of anticoagulation in dialysis patients, careful weighing of risks and benefits on the basis of evidence from other populations is crucial. VTE should be managed with adjusted dose warfarin for most patients. Placement of an inferior vena cava filter is a reasonable option for those patients with unacceptable bleeding risks. Studies are ongoing to assess the safety of some low-molecular-weight heparins (LMWH), which may potentially be useful for long-term anticoagulation in hemodialysis patients. In atrial fibrillation the available data on risk of bleeding, risk of stroke, and patient preferences should all be taken into account when considering long-term anticoagulation. We have constructed an evidence model to help quantitate the risks and benefits for an individual patient. The impact of dialysis on risk of bleeding is such that the risk of bleeding will outweigh the benefit in many patients, and anticoagulation will not be used: in some of these patients aspirin therapy may be an alternative. Finally, in the area of prevention of graft and access thrombosis, some randomized controlled trials are available, but none have to date shown benefit from anticoagulation for primary or secondary prevention of thrombosis, and the risk of bleeding in these studies was high.

Low-molecular-weight heparins for the treatment of acute coronary syndrome and venous thromboembolism in patients with chronic renal insufficiency

The clinical management of patients with renal insufficiency who develop an acute coronary syndrome or venous thromboembolism is a common clinical scenario that is problematic because of the lack of well-designed randomized trials assessing management strategies in such patients. Impaired renal function is common in patients who develop thromboembolic disorders, particularly in elderly patients in whom renal insufficiency is under-recognized. Low-molecular-weight heparins (LMWHs), which are the most widely used anticoagulant for the treatment of patients with an acute coronary syndrome or venous thromboembolism, are eliminated primarily by the kidney and, therefore, pose treatment challenges in patients with impaired renal function. However, there is emerging evidence regarding the use of LMWHs in patients with impaired renal function suggesting that some preparations may be safe in such patients. The objective of this review is to discuss the clinical management of patients with renal insufficiency who develop an acute coronary syndrome or venous thromboembolism, and to explore similarities and differences of LMWHs when used in this clinical setting.

Anticoagulant prophylaxis in special populations with an indwelling epidural catheter or renal insufficiency

The prevention of deep venous thrombosis in postoperative patients who have an indwelling epidural catheter and patients with impaired renal function is a frequently encountered and challenging clinical management problem. Such patients make up a considerable proportion of patients in a medical-surgical intensive care unit. The management of such patients is problematic because low-molecular-weight heparins, the anticoagulant of choice as thromboprophylaxis for many clinical indications, are generally avoided in such patients. This review focuses on anticoagulant prophylaxis in such patients, including reasonable approaches for using low-molecular-weight heparins as thromboprophylaxis.

Dalteparin thromboprophylaxis for critically ill medical-surgical patients with renal insufficiency

PURPOSE

Thromboprophylaxis with low-molecular-weight heparin (LMWH) may be more effective than unfractionated heparin but also more likely to bioaccumulate and potentially cause bleeding in patients with renal insufficiency. The objectives of this study were to assess, among medical-surgical patients in the intensive care unit receiving dalteparin 5,000 IU daily for thromboprophylaxis, (1) the relationship between renal dysfunction and LMWH bioaccumulation as measured by trough anti-Xa levels, (2) the relationship between renal dysfunction and risk of bleeding as measured by a surrogate marker (peak anti-Xa levels), and (3) the relationship between anti-Xa levels, bleeding events, and thrombotic events.

MATERIALS AND METHODS

In this prospective single-center cohort study, we enrolled patients 18 years or older, expected to stay 72 hours or longer, and with a creatinine clearance 30 mL/min or higher at intensive care unit admission. We administered 5,000 IU dalteparin subcutaneously each day. The main phase 1 objective was to detect bioaccumulation of dalteparin by measuring trough anti-Xa levels (22-23 hours post dalteparin). The main phase 2 objective was to examine the relationship between renal dysfunction and peak anti-Xa levels (4 hours post dalteparin). We recorded creatinine clearance daily and bleeding and thrombotic events, blinded to anti-Xa levels.

RESULTS

We enrolled 19 patients aged 62.7 (13.2) years with an APACHE II score of 23.5 (9.4). We measured trough anti-Xa levels on 185 occasions in 19 patients; we measured peak anti-Xa levels on 113 occasions in 11 patients. We identified no bioaccumulation of LMWH in this study, as detected by trough anti-Xa levels. Most peak anti-Xa levels were in the conventional prophylactic range.

CONCLUSIONS

When administered in prophylactic doses to critically ill patients with a wide range of calculated creatinine clearances, we found no evidence of bioaccumulation of dalteparin. If dalteparin does not bioaccumulate, it may be an attractive alternative agent for thromboprophylaxis.

Safety profile of different low-molecular weight heparins used at therapeutic dose

Low-molecular weight heparins (LMWHs) have been shown to be as safe and effective as unfractionated heparin (UFH) for the treatment of acute venous thrombosis and non-life-threatening pulmonary embolism. Different reports have shown that LMWHs may also be used to treat patients with unstable angina or non-Q-wave infarction. The safety of LMWHs used at therapeutic dose has been widely studied in pivotal clinical trials and analysed in several meta-analyses. However, despite the wide development and use of LMWHs, several issues regarding the safety and optimal use of LMWHs remain unanswered. The main adverse effect of LMWHs is bleeding and it is uncertain whether a weight-adjusted dosage regimen without laboratory monitoring can be used in patients with a high risk of bleeding, such as patients with renal failure, elderly patients, obese patients or pregnant women. These patients are usually excluded from clinical trials and only a few studies, not sufficiently powered to estimate efficacy and safety, have been carried out in these special populations. Most of the available data comes from pharmacokinetic or population pharmacodynamic studies or clinical reports. Results in patients with renal impairment who are not undergoing haemodialysis suggest that a reduction in calculated creatinine clearance levels is associated with an increased risk of accumulation of anti-Xa activity, the extent of which differs depending on the individual LMWH and the extent to which the compound is cleared by the kidney. The limited data available regarding the use of therapeutic doses of LMWHs in obese patients suggest that there is no need to cap the dose at a maximal allowable dose. Long-term (3-month) treatment with LMWHs appears to be as effective and safe as oral anticoagulant therapy for the treatment of venous thromboembolism. It appears that each LMWH is a distinct compound with unique pharmacokinetic and pharmacodynamic profiles. Until more data are available regarding these special populations, periodic monitoring of anti-Xa activity levels may be recommended to detect accumulation and/or an overdose and minimise the bleeding risk. The non-haemorrhagic adverse effects of the LMWHs include heparin-induced thrombocytopenia (HIT) and osteoporosis. The incidence of HIT appears to be lower with LMWHs than with UFH; there is currently not enough data to compare the frequency of HIT between the various LMWHs. LMWHs also appear to carry a lower risk of causing osteoporosis than UFH. In conclusion, studies that include special population patients are required to make conclusive recommendations concerning the safety and monitoring of the different LMWHs.

Tinzaparin in the treatment of venous thromboembolism

Low molecular weight heparin (LMWH) has been widely used for the initial treatment of patients presenting with venous thromboembolism. The LMWH, tinzaparin, has been shown in randomised clinical trials to be as effective and safe as unfractionated heparin for the initial treatment of venous thromboembolism and in clinical trials, it has been used in place of warfarin for the long-term treatment of deep vein thrombosis. Tinzaparin can safely be given to patients with significant renal impairment (creatinine clearance of > or = 20 ml/min) and the dose of tinzaparin does not need to be altered in patients with a body mass index of > 25.

Tinzaparin sodium: a review of its pharmacology and clinical use in the prophylaxis and treatment of thromboembolic disease

Tinzaparin sodium (tinzaparin; innohep) is a low molecular weight heparin (LMWH) formed by the enzymatic degradation of porcine unfractionated heparin (UFH). In clinical trials, once-daily subcutaneous (SC) tinzaparin was effective and generally well tolerated in the prophylaxis and treatment of thromboembolic disease. SC tinzaparin 75 anti-Xa IU/kg/day showed similar thromboprophylactic efficacy to adjusted-dosage oral warfarin in patients undergoing total hip arthroplasty; in patients undergoing knee replacement, the incidence of deep vein thrombosis (DVT) was significantly lower with tinzaparin. The drug had similar efficacy to equivalent-dosage SC enoxaparin sodium in orthopaedic surgery. In patients undergoing general surgery, SC tinzaparin 3500 anti-Xa IU/day was of equivalent thromboprophylactic efficacy to SC UFH 5000IU twice daily. Encouraging preliminary results have been obtained with tinzaparin in the prevention of DVT in patients with complete motor paralysis. In the initial treatment of acute proximal DVT and pulmonary embolism, SC tinzaparin 175 anti-Xa IU/kg/day was at least as effective as adjusted-dosage intravenous (IV) UFH. In the outpatient treatment of venous thromboembolism, tinzaparin has demonstrated similar efficacy to dalteparin sodium (dalteparin) and warfarin. Tinzaparin was effective in preventing clotting in haemodialysis circuits; the anticoagulant efficacy of tinzaparin in patients undergoing haemodialysis was similar to that of SC dalteparin and similar to or less than (although in this case the tinzaparin dose was too low for sufficient anticoagulant efficacy) that of IV UFH. Advantages of tinzaparin over UFH and warfarin include ease of administration and lack of need for laboratory monitoring. Tinzaparin is more cost effective than UFH in the treatment of established thromboembolic disease, and home-based treatment with tinzaparin may offer greater cost benefits than hospital-based therapy. Tinzaparin is well tolerated, including in elderly patients and those with renal impairment receiving long-term treatment. Incidences of major bleeding complications were low and reports of heparin-induced thrombocytopenia were infrequent in clinical studies. In conclusion, tinzaparin is a valuable LMWH in the prophylaxis and management of thromboembolic disease.

Low molecular weight heparin treatment in elderly subjects with or without renal insufficiency: new insights between June 2002 and March 2004

PURPOSE OF REVIEW

Low molecular weight heparin has become the treatment of choice for venous thromboembolism events and acute coronary syndromes. In contrast to unfractionated heparin, low molecular weight heparins are mainly excreted by the kidney. Thus, repeated administration of therapeutic doses of low molecular weight heparins may lead to overdosage and/or an accumulation effect in patients with renal impairment, such as the elderly. Moreover, older patients are often excluded from clinical trials. Little evidence is available to assess the risk/benefit ratio of low molecular weight heparins used at therapeutic dosages in elderly patients with or without renal insufficiency in normal clinical practice.

RECENT FINDINGS

Pharmacovigilance data, case reports, and observational studies reporting major bleeding complications in the elderly highlight the potential risk of using low molecular weight heparins at therapeutic dosages in these patients. An evaluation of renal function is thus essential before therapy with low molecular weight heparins is begun. Moreover, multiple-dose pharmacokinetic studies in the elderly have shown that the pharmacokinetic response to impaired renal function, especially the risk of accumulation effect, may differ among preparations of low molecular weight heparins.

SUMMARY

Three approaches to improve the safety of low molecular weight heparins in the elderly are discussed: (1) to replace low molecular weight heparin therapy with monitored unfractionated heparin therapy in cases of severe renal insufficiency, but comparative studies are necessary to clarify whether unfractionated heparin offers better safety in this setting; (2) to use initial reduced dosages in elderly patients with or without renal failure, but these regimens have to be validated for each low molecular weight heparin in terms of efficacy in controlled trials; and (3) to monitor anti-Xa activity to detect any overdosage and/or any accumulation effect of low molecular weight heparins.

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.

Serious adverse incidents with the usage of low molecular weight heparins in patients with chronic kidney disease

BACKGROUND

The aim of the study is to describe serious adverse events in patients with renal insufficiency administered low molecular weight heparins (LMWHs).

METHODS

Systematic case note review from July 2002 to March 2003, Hope Hospital, Salford, UK, was used.

RESULTS

Ten patients experienced an adverse incident on LMWH therapy. Five patients were on maintenance hemodialysis therapy, and 1 patient was on continuous ambulatory peritoneal dialysis therapy. Three patients had calculated creatinine clearances of 5, 11, and 33 mL/min (0.08, 0.18, and 0.55 mL/s), and 1 patient had an estimated glomerular filtration rate of 12 mL/min. Age range was 45 to 89 years. Indications for anticoagulation were suspected pulmonary embolism (1 patient), acute coronary syndrome (7 patients), severe nephrotic syndrome (1 patient), and postoperative venous thromboembolic prophylaxis (1 patient). Three patients also were administered aspirin; 1 patient, clopidogrel; and 3 patients, aspirin and clopidogrel. LMWHs used were enoxaparin (6 patients), tinzaparin (3 patients), and dalteparin sodium (1 patient). Bleeding sources were retroperitoneal (1 patient), spontaneous soft tissue (3 patients), gastrointestinal (2 patients), dialysis catheter and cannula sites (2 patients), hemorrhagic pericardial effusion (1 patient), and intracranial (1 patient). Activated partial thromboplastin time was prolonged in 7 of 10 patients, with no other identifiable cause found. Three patients died despite aggressive resuscitation, including packed red blood cell infusions and protamine sulfate administration. Eight of the 10 prescriptions for LMWHs were either started or continued within our directorate, giving an approximate incidence of major hemorrhagic events in patients with chronic kidney disease of 7.8%.

CONCLUSION

LMWHs administered at fixed-weight doses and without monitoring show unpredictable anticoagulant effects in patients with chronic kidney disease stages 4 and 5, leading to serious and even fatal adverse incidents.

Unresolved issues in anticoagulant therapy

Large randomized clinical trials have clarified some issues of anticoagulation and have led to progress, such as outpatient treatment of acute deep vein thrombosis with low-molecular-weight heparin. However, many uncertainties remain and are reviewed here. When should thrombolytic therapy be used, apart from patients in shock due to pulmonary embolism? How should low-molecular-weight heparin be used in patients with extreme obesity or renal failure? The optimal duration of anticoagulation after venous thromboembolism has been the subject of many debates. With the recognition of an increasing number of risk factors for recurrence, the picture becomes increasingly complex. Lower intensity of anticoagulation with vitamin K antagonists and novel anticoagulant drugs are possible alternatives in extended secondary prophylaxis. For stroke prophylaxis in non-valvular atrial fibrillation, there is a gray zone between the groups where there is a clear indication for aspirin or for vitamin K antagonists. Anticoagulation in connection with cardioversion raises questions regarding optimal postprocedure therapy. Fine tuning of prophylaxis against thromboembolism in patients with prosthetic heart valves requires more studies of subgroups, homogenous for position and type of valve as well as presence of atrial fibrillation. The management of these patients in case of surgical procedures has not been studied properly. Secondary prophylaxis after myocardial infarction may achieve the best effect with vitamin K antagonists at an INR of 2.0-2.5 in combination with low-dose aspirin, but is it really cost-effective? Finally, many controversies exist regarding anticoagulation during pregnancy.