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Dabigatran


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Once a bottle of dabigatran is opened, the medication is considered to be expired after only thirty days. An antidote is available

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  • New drug to prevent stroke/systemic embolism in non valvular AF with additional risk factor
  • An expensive alternative to Warfarin - approximately £3 per day
  • No need to monitor INR which may increase acceptance of anticoagulation therapy for some
Action
  • Direct thrombin inhibitor
  • Clots all depend on formation of fibrin
  • Inhibits the thrombin enzyme preventing conversion of fibrinogen to fibrin
  • Half life 12-17 hrs, 80% renal excreted, antidote available (Praxbind)
Indication and Dose
  • Patients had one non-AF stroke risk factor, which could include
  • Prior stroke or TIA, LVEF < 40%
  • NYHA class 2 to 4 heart failure within the prior six months
  • Age >75 or age 65 to 74 with diabetes
  • Hypertension, Coronary disease.
  • Dabigatran 150 mg bd is superior to Warfarin at reducing risk of stroke or systemic embolism
  • Dabigatran 110 mg bd was non inferior to Warfarin for reducing incidence of stroke or systemic embolism
Indications
Non valvular AF
  • With one of the following previous stroke or TIA, CCF, age > 75 years, diabetes mellitus or hypertension
  • Adult 18 to 74 years Dabigatran 150 mg BD.
  • Adult 75 to 79 years Dabigatran 110 to 150 mg BD.
  • Adult 80 years and over Dabigatran 110 mg BD.
DVT/PE:
  • Adult 18 to 74 years Dabigatran 150 mg BD, following 5+ treatment with a parenteral anticoagulant.
  • Adult 75 to 79 years Dabigatran 110 to 150 mg BD following at least 5 days treatment with a parenteral anticoagulant.
  • Adult 80 years and over Dabigatran 110 mg BD, following at least 5 days treatment with a parenteral anticoagulant.
Interactions
  • Verapamil - use lower dose Dabigatran 110 mg bd
Cautions
  • Other Anticoagulants and antithrombotic drugs or coagulaopathy
  • High HAS BLED score, Poorly controlled BP, Renal failure
  • Bleeding with Dabigatran is harder to stop then with Warfarin as there is no specific antidote
Contraindications
  • Renal failure, Active pathological bleeding, Severe hypersensitivity reaction
  • Significant risk of major bleeding: GI ulcer, oesophageal varices
  • Recent brain, spine, or ophthalmic surgery
  • Recent intracranial haemorrhage, malignant neoplasms, vascular aneurysm
Side effects
  • Overall bleeding risk the same for Warfarin and Dabigatran 150 mg bd
  • Reduced bleeding compared with Warfarin for Dabigatran 110 mg bd
  • Dabigatran significantly lower risk of haemorrhagic stroke compared with Warfarin
  • Dabigatran 150 mg twice daily had significantly higher incidence of major gastrointestinal bleeding
  • Dyspepsia and GI symptoms
Administration Considerations
  • Do not break, chew or crush capsules
  • Keep capsules in original container do not store or place in other containers
  • After opening original container, capsules expire in 120 days
Haemorrhage - intracranial or extracranial
  • In haemorrhage find out when last dose taken as half life 15 hours.
  • Apply pressure to wound or other physical effects. Manage as for haemorrhage.
  • Renal Dialysis is suggested to remove drug.
  • Discuss other options e.g. FFP and prothrombin concentrates with haematologist.
  • Currently there is no actual antidote and this is likely to be an increasing future problem.
References