refludan and melagatran

refludan has been researched along with melagatran* in 8 studies

Reviews

1 review(s) available for refludan and melagatran

ArticleYear
[Clinical use of a new class of anticoagulant drugs: the direct thrombin inhibitors].
    Giornale italiano di cardiologia (2006), 2006, Volume: 7, Issue:11

    The coagulation cascade, and particularly thrombin, plays a very important role in arterial and venous thrombosis. Thereby, it is clear that thrombin inactivation is an optimal strategy for thrombotic disease prevention and treatment. The direct thrombin inhibitors are a new class of anticoagulant drugs directly binding thrombin and blocking its interaction with fibrinogen. The group of direct thrombin inhibitors includes recombinant hirudin (lepirudin and desirudin), bivalirudin, melagatran and its oral precursor, ximelagatran, argotraban and dabigatran. These drugs have several advantages compared to other anticoagulant drugs, and the particular pharmacokinetic properties of some of them could be very important for future management of thromboembolic prophylaxis. The efficacy and safety of these new drugs are evaluated in several clinical trials; however today only few clinical indications are available for the majority of them.

    Topics: Anticoagulants; Antithrombins; Azetidines; Benzylamines; Clinical Trials as Topic; Drug Therapy, Combination; Fibrinolytic Agents; Hirudins; Humans; Peptide Fragments; Recombinant Proteins; Thromboembolism; Treatment Outcome

2006

Other Studies

7 other study(ies) available for refludan and melagatran

ArticleYear
The effect of ex vivo anticoagulants on whole blood platelet aggregation.
    Platelets, 2009, Volume: 20, Issue:1

    Pre- and intraoperative platelet function monitoring is increasingly recommended in order to detect risk factors for bleeding and to target coagulation management. The ideal anticoagulant for accurate platelet aggregometry remains controversial. The aim of this experimental trial was to compare platelet aggregability in whole blood stored in citrate, heparin and direct thrombin inhibitors. Whole blood was drawn from 11 healthy adult volunteers who had not taken any medication in the previous 14 days. Blood was stored in trisodium citrate, unfractionated heparin, melagatran, lepirudin and argatroban. Platelet aggregation was performed using the impedance aggregometer Multiplate (Dynabyte, Munich, Germany) with adenosine diphosphate (ADP), thrombin receptor activating peptide (TRAP), collagen, arachidonic acid and ristocetin as agonists. Samples were analysed immediately after blood sampling (baseline), as well as 30 and 120 min afterwards. At baseline there were no significant differences in aggregability between samples containing direct thrombin inhibitors and heparin. In contrast, aggregation in response to all agonists except for ristocetin was significantly impaired in citrated blood. During storage the response to arachidonic acid and collagen was maintained by direct thrombin inhibitors and heparin, whereas ADP-, TRAP- and ristocetin-induced aggregation varied considerably over time in all ex vivo anticoagulants tested. Pre-analytical procedures should be standardized because storage duration and anticoagulants significantly affect platelet aggregability in whole blood. For point-of-care monitoring with immediate analysis after blood withdrawal all tested direct thrombin inhibitors as well as unfractionated heparin can be used as anticoagulants whereas citrate is not recommended.

    Topics: Adenosine Diphosphate; Anticoagulants; Arachidonic Acid; Arginine; Azetidines; Benzylamines; Blood Platelets; Citric Acid; Collagen; Female; Heparin; Hirudins; Humans; Male; Peptide Fragments; Pipecolic Acids; Platelet Aggregation; Platelet Function Tests; Recombinant Proteins; Ristocetin; Sulfonamides; Time Factors

2009
Differences in the clinically effective molar concentrations of four direct thrombin inhibitors explain their variable prothrombin time prolongation.
    Thrombosis and haemostasis, 2005, Volume: 94, Issue:5

    Four direct thrombin inhibitors (DTIs), lepirudin, bivalirudin, argatroban, and melagatran, differ in their ability to prolong the prothrombin time (PT). Paradoxically, the DTI in clinical use with the lowest affinity for thrombin (argatroban) causes the greatest PT prolongation. We compared the effects of these DTIs on various clotting assays and on inhibition of human and bovine factor Xa (FXa). On a mole-for-mole basis, lepirudin was most able to prolong the PT, activated partial thromboplastin time (APTT), and thrombin clotting time (TCT), whereas argatroban had the least effect. At concentrations that doubled the APTT (argatroban, 1 micromol/l; melagatran, 0.5 micromol/l; bivalirudin, 0.25 micromol/l; lepirudin, 0.06 micromol/l), the rank order for PT prolongation was: argatroban > melagatran > bivalirudin > lepirudin. Although the Ki's associated with inhibition of human FXa by melagatran (1.4 micromol/l) and argatroban (3.2 micromol/l) approach their therapeutic concentrations, inhibition of FXa did not appear to be a major contributor to PT prolongation, since argatroban also prolonged the PT of bovine plasma (despite a Ki for bovine FXa of 2,600 micromol/l). Only melagatran inhibited prothrombinase-bound FXa. We conclude that the differing effects of the DTIs on PT prolongation are primarily driven by their respective molar plasma concentrations required for clinical effect. DTIs with a relatively low affinity for thrombin require high plasma concentrations to double the APTT; these higher plasma concentrations, in turn, quench more of the thrombin generated in the PT, thereby more greatly prolonging the PT.

    Topics: Animals; Anticoagulants; Arginine; Azetidines; Benzylamines; Blood Coagulation; Cattle; Dose-Response Relationship, Drug; Factor Xa; Factor Xa Inhibitors; Glycine; Hirudins; Humans; In Vitro Techniques; Partial Thromboplastin Time; Peptide Fragments; Pipecolic Acids; Prothrombin Time; Recombinant Proteins; Species Specificity; Sulfonamides; Thrombin; Thrombin Time; Thromboplastin

2005
Comparison of two different ecarin clotting time methods.
    Journal of thrombosis and thrombolysis, 2005, Volume: 20, Issue:1

    Ecarin Clotting Time (ECT) assay specifically determines the inhibition of meizothrombin by direct thrombin inhibitors (DTI). Blood coagulation factor levels lowered by vitamin K antagonists (VKA) may prolong ECT. Concomitant treatment of VKA with DTI may influence differently the two published ECT methods.. Lepirudin (100-3,000 ng/ml), argatroban (300--3,000 ng/ml) and melagatran (30--1000 ng/ml) were added to normal plasma (NP; n=12) samples and to plasma of patients on stable vitamin K antagonist therapy with warfarin (VKAP; n=12). ECT assays were performed according to [5] (method 1) and according to [6] (method 2). Data were subjected to multifactorial variance analysis.. Normal ranges were 35.5+/-2.8 s in NP versus 31.8+/-1.2 s in VKAP with method 1 (p< 0.001) and 44.3+/-3.9 s in NP vs. 51.4+/-8.3 s in VKAP with method 2 (p< 0.004). Besides the inhibitors (p<0.0001), the method used (p<0.0001) and the group (NP vs. VKAP, p=0.003) had an influence on the ECT. Inhibitors (p< 0.02) or method used (p< 0.03) and the group (NP vs. VKAP, p=0.0001) influenced also the ECT ratio.. Both ECT methods are suitable for monitoring different DTIs over a large linear range with both methods during concomitant treatments with vitamin K antagonists. The ECT ratio improves but not abolishes the differences between the methods. Additive effects of vitamin K antagonists on ECT methods have to be taken into consideration in clinical routine.

    Topics: Antithrombins; Azetidines; Benzylamines; Blood Coagulation; Endopeptidases; Glycine; Hirudins; Humans; In Vitro Techniques; Recombinant Proteins; Viper Venoms

2005
In vitro effect of melagatran and lepirudin on clot-bound thrombin.
    Thrombosis research, 2003, Jun-01, Volume: 110, Issue:4

    Topics: Anticoagulants; Azetidines; Benzylamines; Glycine; Hirudins; Humans; In Vitro Techniques; Recombinant Proteins; Thrombin; Thrombosis

2003
Effects of lepirudin, argatroban and melagatran and additional influence of phenprocoumon on ecarin clotting time.
    Thrombosis research, 2003, Volume: 111, Issue:1-2

    Direct thrombin inhibitors (DTI) prolong the ecarin clotting time (ECT). Oral anticoagulants (OA) decrease prothrombin levels and thus interact with actions of DTIs on the ECT method during concomitant therapy.. Actions of lepirudin, argatroban and melagatran on ECT were investigated in normal plasma (NP) and in plasma of patients (n=23 each) on stable therapy with phenprocoumon (OACP). Individual line characteristics were tested statistically.. Control ECT in OACP was prolonged compared to NP (50.1+/-0.9 vs. 45.7+/-0.8 s; p<0.001). Lepirudin prolonged the ECT linearly. Argatroban and melagatran delivered biphasic dose-response curves. OA showed additive effects on the ECT of lepirudin but not of argatroban and melagatran. Both in NP and OACP, the first and second slopes of melagatran were steeper compared to argatroban (primary analysis; p<0.001). When using the same drug, slopes in OACP were steeper than in NP (secondary analysis; p<0.001). At similar molar concentrations, the crossing points of both slopes were significantly higher with melagatran (323.1+/-11.0 s in NP and 333.2+/-8.2 s in OACP) than with argatroban (219.6+/-14.7 and 248.4+/-15.2 s) corresponding to ratios of 7.1+/-0.2 and 6.7+/-0.2 (melagatran) vs. 4.8+/-0.3 and 4.9+/-03 with argatroban (p<0.0001).. The patterns of interactions between vitamin K antagonists and DTI effects are different for bivalent (increase of slope without affecting linearity) and monovalent inhibitors (slight increase or alteration of nonlinear slopes), but there are also differences between the two monovalent inhibitors on thrombin inhibition as determined by ECT.

    Topics: Anticoagulants; Azetidines; Benzylamines; Blood Coagulation; Blood Coagulation Tests; Fibrinolytic Agents; Glycine; Hirudins; Humans; Kinetics; Outpatients; Phenprocoumon; Recombinant Proteins; Reference Values

2003
Monitoring of anticoagulant effects of direct thrombin inhibitors.
    Seminars in thrombosis and hemostasis, 2002, Volume: 28, Issue:4

    Monitoring of direct thrombin inhibitors with the activated partial thromboplastin time (aPTT) is limited by poor linearity and reproducibility. Recently, direct prothrombin activation methods have been developed for coagulation analysis: ecarin clotting time (ECT) and prothrombinase-induced clotting time (PiCT). Laboratory monitoring of the direct thrombin inhibitors lepirudin, argatroban, and melagatran was analyzed and compared with monitoring unfractionated heparin (UFH). Plasma samples of six healthy donors were spiked with lepirudin and argatroban extending to 3000 ng/mL, melagatran extending to 1000 ng/mL, and UFH up to 0.48 IU/mL. Clotting times of aPTT (two reagents), ECT, PiCT, and prothrombin time were determined in a KC 10, a micro instrument. At 3000 ng/mL ECT values were 339.1 +/- 25.0 seconds with lepirudin and 457.5 +/- 29.5 seconds with argatroban. ECT was 586.0 +/- 38.2 seconds with 1000 ng/mL melagatran. The PiCT method provided clotting times of 137.0 +/- 8.4 seconds with UFH, 128.0 +/- 23.4 seconds with lepirudin, and 151 +/- 23.9 seconds with argatroban, and 153.5 +/- 9.9 seconds with melagatran, with the concentrations mentioned. ECT is more sensitive to therapeutic drug concentration ranges than aPTT (prolongations of 3-7 versus 2-3). PiCT yields comparable results with direct thrombin inhibitors and UFH. This method could therefore be suitable for monitoring both drug groups.

    Topics: Anticoagulants; Arginine; Azetidines; Benzylamines; Blood Coagulation Tests; Drug Monitoring; Glycine; Heparin; Hirudins; Humans; Pipecolic Acids; Recombinant Proteins; Sensitivity and Specificity; Sulfonamides; Thrombin

2002
Influence of lepirudin, argatroban, and melagatran on prothrombin time and additional effect of oral anticoagulation.
    Clinical chemistry, 2002, Volume: 48, Issue:10

    Topics: Administration, Oral; Anticoagulants; Arginine; Azetidines; Benzylamines; Drug Synergism; Glycine; Hirudins; Humans; Phenprocoumon; Pipecolic Acids; Prothrombin Time; Recombinant Proteins; Sulfonamides

2002