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Information |
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Drug Groups
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approved |
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Description
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Dabigatran etexilate is an oral prodrug that is metabolized by a serum esterase to dabigatran. It is a synthetic, competitive and reversible direct thrombin inhibitor. Inhibition of thrombin disrupts the coagulation cascade and inhibits the formation of clots. Dabigatran etexilate may be used to decrease the risk of venous thromboembolic events in patients who have undergone total hip or knee replacement surgery, or to prevent stroke and systemic embolism in patients with atrial fibrillation, in whom anticoagulation therapy is indicated. |
| Indication |
Dabigatran is indicated for the prevention of venous thromboembolic events in patients who have undergone elective hip or knee replacement surgery (based on RE-NOVATE, RE-MODEL, and RE-MOBILIZE trials). In 2010, it was approved in the US and Canada for prevention of stroke and systemic embolism in patients with atrial fibrillation (approval based on the RE-LY trial). Contraindications: severe renal impairment (CrCL < 30 ml/min); haemorrhagic manifestations, bleeding diathesis or spontaneous or pharmacologic impairment of haemostasis; lesions at risk of clinically significant bleeding (e.g. extensive cerebral infarction (haemorrhagic or ischemic) in the last 6 months, active peptic ulcer disease); concomitant treatment with P-glycoprotein inhibitors (e.g. oral ketoconazole, verapamil); and those with known hypersensitivity to dabigatran, dabigatran etexilate or any ingredient used in the formulation or component of the container. |
| Pharmacology |
Dabigatran etexilate is an inactive pro-drug that gets converted to dabigatran, the active form, by esterase-catalyzed hydrolysis in the plasma and liver. Dabigatran, the main active principle in plasma, is a rapid-acting competitive and reversible direct inhibitor of thrombin. Thrombin, a serine protease, is responsible for the conversion of fibrinogen to fibrin during the coagulation cascade. Inhibition of thrombin consequently prevents thrombus development. Dabigatran inhibits free thrombin, fibrin-bound thrombin and thrombin-induced platelet aggregation. |
| Toxicity |
The most common adverse reactions include dyspepsia or gastritis-like symptoms. The approximate lethal dose in rats and mice was observed at single oral doses of > 2000 mg/kg. Oral doses of 600 mg/kg did not induce any toxicologically meaningful changes in dogs and Rhesus monkeys. Dabigatran was well-tolerated in rats and Rhesus monkeys during repeat-dose toxicity studies. No evidence of mutagenic potential. |
| Affected Organisms |
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Humans and other mammals |
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| Biotransformation |
Dabigatran is typically metabolised by esterases and microsomal carboxylesterases. CYP450 enzymes do not seem to be involved. Pharmacologically active acylglucoronides are formed via conjugation. Four positional isomers, 1-O, 2-O, 3-O, and 4-O, acylglucuronides exist, each accounting for less than 10% of total plasma dabagatran. |
| Absorption |
Peak plasma concentrations were achieved in 6 hours in post surgical patients. In healthy patients, maximum concentrations were achieved in 0.5 to 2 hours. The absolute bioavailability of dabigatran in the body after administration of dabigatran etexilate was 6.5%. Food does not affect the bioavailability of dabigatran etexilate, but it delays the time to peak plasma concentrations by 2 hours. Oral bioavailability may increase by up to 75% when pellets are taken out of the hydroxypropylmethylcellulose (HPMC) capsule. Therefore, capsules should not be opened and pellets taken alone. |
| Half Life |
12-14 hours in healthy volunteers. 14-17 hours in patients treated for prevention of venous thromboembolism following hip- or knee-replacement surgery. |
| Protein Binding |
Relatively low binding (34-35%) to plasma proteins. |
| Elimination |
Mainly excreted in urine (85%). Fecal excretion accounts for 6% of the orally administered dose. Dabigatran is primarily eliminated unchanged via the kidneys at a rate of 100 ml/min corresponding to the glomerular filtration rate. |
| Distribution |
Moderate tissue distribution with Vd of 60-70L |
| References |
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Bauer KA: New oral anticoagulants in development: potential for improved safety profiles. Rev Neurol Dis. 2010;7(1):1-8.
[Pubmed]
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Connolly SJ, Ezekowitz MD, Yusuf S, Eikelboom J, Oldgren J, Parekh A, Pogue J, Reilly PA, Themeles E, Varrone J, Wang S, Alings M, Xavier D, Zhu J, Diaz R, Lewis BS, Darius H, Diener HC, Joyner CD, Wallentin L: Dabigatran versus warfarin in patients with atrial fibrillation. N Engl J Med. 2009 Sep 17;361(12):1139-51. Epub 2009 Aug 30.
[Pubmed]
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Wolowacz SE, Roskell NS, Plumb JM, Caprini JA, Eriksson BI: Efficacy and safety of dabigatran etexilate for the prevention of venous thromboembolism following total hip or knee arthroplasty. A meta-analysis. Thromb Haemost. 2009 Jan;101(1):77-85.
[Pubmed]
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Ginsberg JS, Davidson BL, Comp PC, Francis CW, Friedman RJ, Huo MH, Lieberman JR, Muntz JE, Raskob GE, Clements ML, Hantel S, Schnee JM, Caprini JA: Oral thrombin inhibitor dabigatran etexilate vs North American enoxaparin regimen for prevention of venous thromboembolism after knee arthroplasty surgery. J Arthroplasty. 2009 Jan;24(1):1-9. Epub 2008 Apr 14.
[Pubmed]
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Eriksson BI, Dahl OE, Buller HR, Hettiarachchi R, Rosencher N, Bravo ML, Ahnfelt L, Piovella F, Stangier J, Kalebo P, Reilly P: A new oral direct thrombin inhibitor, dabigatran etexilate, compared with enoxaparin for prevention of thromboembolic events following total hip or knee replacement: the BISTRO II randomized trial. J Thromb Haemost. 2005 Jan;3(1):103-11.
[Pubmed]
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Di Nisio M, Middeldorp S, Buller HR: Direct thrombin inhibitors. N Engl J Med. 2005 Sep 8;353(10):1028-40.
[Pubmed]
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Stangier J, Eriksson BI, Dahl OE, Ahnfelt L, Nehmiz G, Stahle H, Rathgen K, Svard R: Pharmacokinetic profile of the oral direct thrombin inhibitor dabigatran etexilate in healthy volunteers and patients undergoing total hip replacement. J Clin Pharmacol. 2005 May;45(5):555-63.
[Pubmed]
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Ezekowitz MD, Reilly PA, Nehmiz G, Simmers TA, Nagarakanti R, Parcham-Azad K, Pedersen KE, Lionetti DA, Stangier J, Wallentin L: Dabigatran with or without concomitant aspirin compared with warfarin alone in patients with nonvalvular atrial fibrillation (PETRO Study). Am J Cardiol. 2007 Nov 1;100(9):1419-26. Epub 2007 Aug 17.
[Pubmed]
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Eriksson BI, Dahl OE, Rosencher N, Kurth AA, van Dijk CN, Frostick SP, Kalebo P, Christiansen AV, Hantel S, Hettiarachchi R, Schnee J, Buller HR: Oral dabigatran etexilate vs. subcutaneous enoxaparin for the prevention of venous thromboembolism after total knee replacement: the RE-MODEL randomized trial. J Thromb Haemost. 2007 Nov;5(11):2178-85.
[Pubmed]
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Eriksson BI, Dahl OE, Rosencher N, Kurth AA, van Dijk CN, Frostick SP, Prins MH, Hettiarachchi R, Hantel S, Schnee J, Buller HR: Dabigatran etexilate versus enoxaparin for prevention of venous thromboembolism after total hip replacement: a randomised, double-blind, non-inferiority trial. Lancet. 2007 Sep 15;370(9591):949-56.
[Pubmed]
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"European Medicines Agency":http://www.ema.europa.eu/humandocs/PDFs/EPAR/pradaxa/H-829-en6.pdf |
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Abrams P and Marzella N: Dabigatran (Rendix): A Promising New Oral Direct Thrombin Inhibitor. Drug Forecast. 2007;32(5):271-5.
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