Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0038454 (stroke)
 147,016 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Melagatran is a potent direct thrombin inhibitor and it is an effective agent in the prevention of stroke in patients with atrial fibrillation (AF); however, there are no data about its actions in the treatment of acute ischemic stroke. In the present study, we evaluated the neuroprotective actions of melagatran using an embolic model of stroke in rats. We first examined protective effects at increasing doses of melagatran. Then, we examined the effects of melagatran administered at different time points following middle cerebral artery (MCA) occlusion. We also evaluated the effects of combination therapy with melagatran and tissue plasminogen activator (tPA) in this model. Finally, we examined if melagatran can improve compromised microcirculation in the ischemic injured brain. The medication alone or in combination with tPA was well tolerated. Melagatran reduced ischemic brain injury in a dose-response manner, and also in a time dependent manner. Combination treatment of melagatran and tPA was superior to either treatment alone. There was no significant increase in symptomatic or asymptomatic hemorrhages in the treated animals. Melagatran treatment also reduced perfusion deficits in the ischemic injured brain. The present study is the first report on the usefulness of melagatran in embolic ischemic stroke. Our research shows that melagatran is an effective agent in the treatment of ischemic brain injury. The protective effects of this medication are likely due to its actions in enhancing thrombus dissolution and preventing formation of microthrombosis in the ischemic injured brain. Finally, the combination with melagatran and tPA appears safe and superior to each treatment offered alone.
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PMID:Treatment with melagatran alone or in combination with thrombolytic therapy reduced ischemic brain injury. 1859 97

The incidence of stroke in patients with atrial fibrillation (AF) is five times greater than that in age-matched controls. Warfarin reduces this incidence by two thirds and is the most effective agent for this indication. However, despite its efficacy, warfarin management is tedious and is useful only in a subsegment of the population who needs anticoagulation and has no contraindications. Many agents are poised to replace warfarin as an effective anticoagulant for stroke prevention in AF. The direct thrombin inhibitor dabigatran is furthest along in clinical development, followed by the factor Xa inhibitors rivaroxaban and apixaban. All these agents seem effective, and none appears mechanistically superior over another. Dabigatran's advantage is that it was tested in two dosages in a phase 3 evaluation based on earlier phase 2 studies in patients with AF, whereas dosage data for the other agents were extrapolated from phase 2 programs for venous thromboembolism prevention. The vitamin K antagonist ATI-5923 offers clinical benefits similar to warfarin's, but with no or fewer drug-drug interactions, potentially greater time in therapeutic range, and probably less need for dose adjustment and laboratory monitoring. It challenges the newer mechanistic agents in efficacy and raises the bar for comparison in future head-to-head trials. Further analysis and clinical trial testing are still needed to determine whether one or all of these agents are effective anticoagulants for stroke prevention in patients with AF.
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PMID:New developments in anticoagulation for atrial fibrillation. 1881 28

Polymorphisms in CYP2C9, a critical cytochrome P-450 enzyme in the metabolism of warfarin, alters its clearance and affects dosing. CYP*1 has higher activity than either the *2 or *3 variants, and patients with the *2 or *3 variants require a lower dose. VKORC1 is the enzyme inhibited by warfarin, and its levels are affected by several polymorphisms that can be divided into high or low level haplotypes, and patients with high level haplotypes require higher warfarin doses. The use of algorithms for dosing that incorporate pharmacogenomic information perform better than those using clinical data alone. Considerable effort is ongoing to develop new oral anticoagulants as alternatives to warfarin, and three agents are in advanced development. Dabigatran is an oral direct thrombin inhibitor that has been compared with enoxaparin for prevention of VTE following hip or knee replacement. Based on non-inferiority results in European trials, it has now been approved for marketing in Europe. Phase III trials with a new oral Xa inhibitor, rivaroxaban, have been completed in hip or knee replacement, and rivaroxaban was superior to enoxaparin in prevention of VTE with no increase in bleeding complications. Phase III studies with apixaban, another oral Xa inhibitor, are in progress. These agents are also being evaluated in large studies for prevention of stroke in atrial fibrillation and for VTE treatment.
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PMID:New issues in oral anticoagulants. 1907 93

Vitamin K antagonists (VKAs) are effective for stroke prevention in patients with atrial fibrillation (AF) but are difficult to use. Dabigatran etexilate is a prodrug that is rapidly converted to the active direct thrombin inhibitor dabigatran. It is administered in a fixed dose without laboratory monitoring and is being compared with warfarin (international normalized ratio 2-3) in the RE-LY trial. Two doses of dabigatran (110 and 150 mg BID) are being evaluated. RE-LY is a phase 3, prospective, randomized, open-label multinational (44 countries) trial of patients with nonvalvular AF and at least 1 risk factor for stroke. Recruitment concluded with a total of 18,113 patients. Patients who were VKA-naive and experienced are included in balanced proportions. The primary outcome is stroke (including hemorrhagic) or systemic embolism. Safety outcomes are bleeding, liver function abnormalities, and other adverse events. Adjudication of end points is blinded to drug assignment. The trial is expected to accrue a minimum of 450 events with a minimum 1-year of follow-up. RE-LY is the largest AF stroke prevention trial yet undertaken. It is unique because it includes equal numbers of VKA-experienced and naive patients and evaluates 2 different dosages of dabigatran, which may allow tailoring of dosing to individual patient needs. The worldwide site distribution and broad range of stroke risk further increase the general applicability of the trial. Results are expected in 2009.
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PMID:Rationale and design of RE-LY: randomized evaluation of long-term anticoagulant therapy, warfarin, compared with dabigatran. 1937 4

As the population ages, the burden of thromboembolic disease increases. The development of new anticoagulants that overcome the shortcomings of the vitamin K antagonists represents an important advance.Clinical evaluation of new anticoagulants typically begins in short-term indications, such as prophylaxis against venous thromboembolism in patients undergoing orthopaedic surgery, followed by investigation in chronic conditions, such as stroke prevention in patients with atrial fibrillation. Factors for consideration in clinical trials include methodological issues (blinded versus open-label; active-control statistical designs; patient selection, etc.). Despite its subsequent withdrawal, clinical trials of ximelagatran demonstrated the efficacy of fixed doses of an oral, direct thrombin inhibitor for prevention of thromboembolism. Direct and indirect inhibition of activated Factor X is another target for new anticoagulants. Evidence-based data from trials such as these will pave the way for new anticoagulants, with the goal of bringing optimum prophylactic therapy to those requiring anticoagulation.
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PMID:What can ongoing clinical trials of anticoagulants demonstrate? 1955 27

Dabigatran etexilate is a novel, oral reversible direct thrombin inhibitor in the clinical development for the treatment and prevention of thromboembolic diseases. Clinical data indicate that dabigatran etexilate has immediate onset of effect, no need for monitoring, predictable and consistent pharmacokinetics and pharmacodynamics-all features that differentiate it from oral vitamin K antagonists (VKAs). Completed phase III studies demonstrated a comparable efficacy and safety profile to enoxaparin in the prevention of venous thromboembolism (VTE) after orthopedic surgery. Ongoing phase III trials are now evaluating the long-term use of dabigatran etexilate for the treatment and secondary prevention of VTE and for prevention of stroke in patients with atrial fibrillation, as a replacement for VKAs. With an immediate, reliable, and predictable anticoagulant effect without the need for coagulation monitoring and the lack of long-term safety concerns, dabigatran etexilate may be a prospective candidate that offers additional benefit over VKAs and parenteral anticoagulants in these settings.
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PMID:Dabigatran etexilate: future directions in anticoagulant treatment. 1967 90

Dabigatran etexilate is a novel, oral reversible direct thrombin inhibitor that is rapidly absorbed and converted to its active form, dabigatran. Dabigatran has been shown to be a potent, competitive, and reversible inhibitor of thrombin, inhibiting both thrombin activity and generation. Studies in healthy volunteers and in patients undergoing orthopedic surgery indicate that dabigatran has a predictable pharmacokinetic profile, allowing for a fixed-dose regimen without the need for coagulation monitoring. In healthy volunteers, peak plasma concentrations of dabigatran are reached approximately 2 hours after oral administration. The elimination half-life is 12 to 14 hours, with clearance predominantly occurring via renal excretion of unchanged drug. Dabigatran is not metabolized by cytochrome P450 isoenzymes, has no interactions with food, and also has a low potential for drug-drug interactions. The pharmacokinetic profile of dabigatran is consistent across a broad range of different patient populations and is unaffected by gender, body weight, ethnic origin, obesity, and mild-to-moderate hepatic impairment. Small differences in dabigatran pharmacokinetics associated with age are attributable to variation in renal function. Dabigatran etexilate produces a predictable pharmacodynamic effect and requires no coagulation monitoring. It has been approved in the European Union (EU) and Canada for prophylaxis of thromboembolism in patients undergoing total knee or hip arthroplasty. Ongoing clinical trials are investigating its use in the treatment of venous thromboembolism, prevention of stroke in patients with nonvalvular atrial fibrillation, and treatment of thromboembolic complications, following acute coronary syndromes.
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PMID:Pharmacology, pharmacokinetics, and pharmacodynamics of dabigatran etexilate, an oral direct thrombin inhibitor. 1969 42

Argatroban is a synthetic direct thrombin inhibitor with a relative short elimination half-life of 45 minutes and elimination which is predominantly performed via hepatic metabolism. Argatroban anticoagulation has been systematically studied in patients exhibiting the heparin-induced thrombocytopenia (HIT)/thrombosis syndrome and demonstrated to be a safe and effective therapy in this indication. Moreover, in smaller studies argatroban has also been assessed in special clinical settings in non-HIT patients. The current review presents the pharmacology of argatroban, data regarding monitoring of the agent, and an overview of the results of the major clinical trials assessing argatroban anticoagulation in HIT patients. Additionally, data from clinical trials with argatroban use outside HIT, in more special indications such as in percutaneous coronary intervention, stroke, renal replacement therapy, and intensive care medicine, are reviewed.
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PMID:The direct thrombin inhibitor argatroban: a review of its use in patients with and without HIT. 1970 20

AZD0837 is an investigational oral anticoagulant which is converted to the active form, AR-H067637, a selective direct thrombin inhibitor. The present study, a multicentre, randomised, parallel-group, dose-guiding study, assessed the safety and tolerability of an immediate-release formulation of AZD0837 compared with dose-adjusted warfarin in the prevention of stroke and systemic embolic events in atrial fibrillation (AF) patients. Two hundred fifty AF patients with at least one additional risk factor for stroke were randomised to receive either immediate-release AZD0837 (150mg twice daily [bid] or 350mg bid, blinded treatment) or dose-adjusted warfarin (international normalised ratio 2.0-3.0, open treatment) for three months. The safety and tolerability of 150mg bid AZD0837 appeared to be as good as that of warfarin. Total bleeding events were six with 150mg bid AZD0837, 15 with 350mg bid AZD0837 and eight with warfarin. Alanine aminotransferase elevations (>3xupper limit of normal) were infrequent, without apparent differences between treatment groups. A numerically higher incidence of serious adverse events was observed with 350mg bid AZD0837 compared with 150mg bid, with six of 13 being cardiac related, all with different diagnoses. An increase in mean serum creatinine of approximately 10% was observed in both AZD0837 groups, which returned to baseline after completion of therapy. There were no strokes, transient ischaemic attacks or cerebral haemorrhages with any of the treatments. In conclusion, the safety and tolerability of 150mg bid immediate-release AZD0837 appeared to be as good as that of dose-adjusted warfarin. However, larger studies will be needed to define the safety profile of AZD0837.
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PMID:Safety and tolerability of an immediate-release formulation of theoral direct thrombin inhibitor AZD0837 in the prevention of stroke and systemic embolism in patients with atrial fibrillation. 2007 57

Aspirin is widely used for the prevention of recurrent stroke in patients with transient ischaemic attack (TIA) and ischaemic stroke of arterial origin, because it is effective and inexpensive. Clopidogrel and the combination of aspirin and extended-release dipyridamole are more effective than aspirin, but are also much more expensive. No other antithrombotic regimens provide significant advantages over aspirin, although cilostazol and the novel platelet protease activated receptor-1 antagonist, SCH 530348, are currently being evaluated. For patients with TIA and ischaemic stroke of cardiac origin due to atrial fibrillation, vitamin K antagonists (VKAs) are highly effective in preventing recurrent ischaemic stroke but have important limitations and are thus underused. Antiplatelet therapy is much less effective than VKAs. The direct thrombin inhibitor, dabigatran etexilate, has shown efficacy over warfarin in a recent trial. Other new anticoagulants, including the oral factor Xa inhibitors, rivaroxaban, apixaban, and edoxaban, the parenteral factor Xa inhibitor, idrabiotaparinux, and the novel VKA, tecarfarin, are currently being assessed.
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PMID:Antithrombotic drugs for patients with ischaemic stroke and transient ischaemic attack to prevent recurrent major vascular events. 2017 Aug 41


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